fix: Resolve merge conflict in server/mod.rsmakima/discuss-contract-feature

Combine imports from both branches - include both chains and contract_discuss handlers.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

16 files changed, 3210 insertions, 11 deletions

diff --git a/makima/src/bin/makima.rs b/makima/src/bin/makima.rs
index af9832b..2037b47 100644
--- a/makima/src/bin/makima.rs
+++ b/makima/src/bin/makima.rs
@@ -6,7 +6,8 @@ use std::sync::Arc;
 
 use makima::daemon::api::{ApiClient, CreateContractRequest};
 use makima::daemon::cli::{
-    Cli, CliConfig, Commands, ConfigCommand, ContractCommand, SupervisorCommand, ViewArgs,
+    Cli, CliConfig, Commands, ConfigCommand, ContractCommand, ChainCommand,
+    SupervisorCommand, ViewArgs,
 };
 use makima::daemon::tui::{self, Action, App, ListItem, ViewType, TuiWsClient, WsEvent, OutputLine, OutputMessageType, WsConnectionState, RepositorySuggestion};
 use makima::daemon::config::{DaemonConfig, RepoEntry};
@@ -30,6 +31,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
         Commands::Contract(cmd) => run_contract(cmd).await,
         Commands::View(args) => run_view(args).await,
         Commands::Config(cmd) => run_config(cmd).await,
+        Commands::Chain(cmd) => run_chain(cmd).await,
     }
 }
 
@@ -793,6 +795,218 @@ async fn run_config(cmd: ConfigCommand) -> Result<(), Box<dyn std::error::Error
     }
 }
 
+/// Run chain commands.
+async fn run_chain(
+    cmd: ChainCommand,
+) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    use makima::daemon::chain::{parse_chain_file, validate_dag, ChainRunner};
+
+    match cmd {
+        ChainCommand::Run(args) => {
+            eprintln!("Loading chain from: {}", args.file.display());
+
+            // Load and validate chain
+            let chain = parse_chain_file(&args.file)?;
+            validate_dag(&chain)?;
+
+            if args.dry_run {
+                eprintln!("\n=== DRY RUN - No changes will be made ===\n");
+            }
+
+            let runner = ChainRunner::new(args.common.api_url.clone(), args.common.api_key.clone());
+
+            // Show execution order
+            let order = runner.get_execution_order(&chain)?;
+            eprintln!("Execution order:");
+            for (i, name) in order.iter().enumerate() {
+                eprintln!("  {}. {}", i + 1, name);
+            }
+            eprintln!();
+
+            // Show visualization
+            eprintln!("{}", runner.visualize_dag(&chain));
+
+            if args.dry_run {
+                eprintln!("\n=== DRY RUN COMPLETE ===");
+                let request = runner.to_create_request(&chain);
+                println!("{}", serde_json::to_string_pretty(&request)?);
+            } else {
+                // Create chain via API
+                let client = ApiClient::new(args.common.api_url, args.common.api_key)?;
+                let request = runner.to_create_request(&chain);
+                let result = client.create_chain(request).await?;
+                println!("{}", serde_json::to_string(&result.0)?);
+            }
+        }
+        ChainCommand::Status(args) => {
+            let client = ApiClient::new(args.common.api_url, args.common.api_key)?;
+            let result = client.get_chain(args.chain_id).await?;
+            println!("{}", serde_json::to_string(&result.0)?);
+        }
+        ChainCommand::List(args) => {
+            let client = ApiClient::new(args.common.api_url, args.common.api_key)?;
+            let result = client.list_chains(args.status.as_deref(), args.limit).await?;
+            println!("{}", serde_json::to_string(&result.0)?);
+        }
+        ChainCommand::Contracts(args) => {
+            let client = ApiClient::new(args.common.api_url, args.common.api_key)?;
+            let result = client.get_chain_contracts(args.chain_id).await?;
+            println!("{}", serde_json::to_string(&result.0)?);
+        }
+        ChainCommand::Graph(args) => {
+            let client = ApiClient::new(args.common.api_url, args.common.api_key)?;
+            let result = client.get_chain_graph(args.chain_id).await?;
+
+            // Get the graph data
+            if args.with_status {
+                // Enhanced ASCII visualization with status
+                if let Some(nodes) = result.0.get("nodes").and_then(|v| v.as_array()) {
+                    let mut by_depth: std::collections::HashMap<i32, Vec<(&str, &str)>> =
+                        std::collections::HashMap::new();
+
+                    for node in nodes {
+                        let name = node.get("name").and_then(|v| v.as_str()).unwrap_or("?");
+                        let status = node
+                            .get("status")
+                            .and_then(|v| v.as_str())
+                            .unwrap_or("pending");
+                        let depth = node.get("depth").and_then(|v| v.as_i64()).unwrap_or(0) as i32;
+                        by_depth.entry(depth).or_default().push((name, status));
+                    }
+
+                    let chain_name = result
+                        .0
+                        .get("name")
+                        .and_then(|v| v.as_str())
+                        .unwrap_or("Chain");
+                    println!("Chain: {}", chain_name);
+                    println!();
+
+                    let max_depth = by_depth.keys().max().copied().unwrap_or(0);
+                    for depth in 0..=max_depth {
+                        if let Some(contracts) = by_depth.get(&depth) {
+                            let indent = "  ".repeat(depth as usize);
+                            for (name, status) in contracts {
+                                let status_icon = match *status {
+                                    "completed" | "done" => "\u{2713}",
+                                    "active" | "running" | "in_progress" => "\u{21bb}",
+                                    "failed" | "error" => "\u{2717}",
+                                    _ => "\u{25cb}",
+                                };
+                                println!("{}[{}] {} {}", indent, name, status_icon, status);
+                            }
+                            if depth < max_depth {
+                                println!("{}  |", indent);
+                                println!("{}  v", indent);
+                            }
+                        }
+                    }
+                }
+            } else {
+                // Simple JSON output
+                println!("{}", serde_json::to_string_pretty(&result.0)?);
+            }
+        }
+        ChainCommand::Validate(args) => {
+            eprintln!("Validating chain file: {}", args.file.display());
+
+            match parse_chain_file(&args.file) {
+                Ok(chain) => {
+                    match validate_dag(&chain) {
+                        Ok(()) => {
+                            eprintln!("\u{2713} Chain definition is valid");
+                            eprintln!("  Name: {}", chain.name);
+                            eprintln!("  Contracts: {}", chain.contracts.len());
+
+                            // Show any warnings
+                            for contract in &chain.contracts {
+                                if contract.tasks.is_none() || contract.tasks.as_ref().map(|t| t.is_empty()).unwrap_or(true) {
+                                    eprintln!("  \u{26a0} Contract '{}' has no tasks", contract.name);
+                                }
+                            }
+
+                            println!(r#"{{"valid": true, "name": "{}", "contractCount": {}}}"#,
+                                chain.name, chain.contracts.len());
+                        }
+                        Err(e) => {
+                            eprintln!("\u{2717} DAG validation failed: {}", e);
+                            println!(r#"{{"valid": false, "error": "{}"}}"#, e);
+                            std::process::exit(1);
+                        }
+                    }
+                }
+                Err(e) => {
+                    eprintln!("\u{2717} Parse error: {}", e);
+                    println!(r#"{{"valid": false, "error": "{}"}}"#, e);
+                    std::process::exit(1);
+                }
+            }
+        }
+        ChainCommand::Preview(args) => {
+            eprintln!("Previewing chain: {}", args.file.display());
+
+            let chain = parse_chain_file(&args.file)?;
+            validate_dag(&chain)?;
+
+            let runner = ChainRunner::new(String::new(), String::new());
+
+            // Show chain info
+            println!("Chain: {}", chain.name);
+            if let Some(desc) = &chain.description {
+                println!("Description: {}", desc);
+            }
+            if let Some(repo) = &chain.repository_url {
+                println!("Repository: {}", repo);
+            }
+            println!();
+
+            // Show execution order
+            let order = runner.get_execution_order(&chain)?;
+            println!("Execution Order:");
+            for (i, name) in order.iter().enumerate() {
+                let contract = chain.contracts.iter().find(|c| c.name == *name).unwrap();
+                let deps = contract
+                    .depends_on
+                    .as_ref()
+                    .map(|d| d.join(", "))
+                    .unwrap_or_else(|| "(none)".to_string());
+                let task_count = contract.tasks.as_ref().map(|t| t.len()).unwrap_or(0);
+                println!(
+                    "  {}. {} [type: {}, tasks: {}, depends: {}]",
+                    i + 1,
+                    name,
+                    contract.contract_type,
+                    task_count,
+                    deps
+                );
+            }
+            println!();
+
+            // Show DAG visualization
+            println!("{}", runner.visualize_dag(&chain));
+
+            // Show loop config if enabled
+            if let Some(lc) = &chain.loop_config {
+                if lc.enabled {
+                    println!("\nLoop Configuration:");
+                    println!("  Max iterations: {}", lc.max_iterations);
+                    if let Some(check) = &lc.progress_check {
+                        println!("  Progress check: {}", check);
+                    }
+                }
+            }
+        }
+        ChainCommand::Archive(args) => {
+            let client = ApiClient::new(args.common.api_url, args.common.api_key)?;
+            eprintln!("Archiving chain {}...", args.chain_id);
+            let result = client.archive_chain(args.chain_id).await?;
+            println!("{}", serde_json::to_string(&result.0)?);
+        }
+    }
+
+    Ok(())
+}
+
 /// Load contracts from API
 async fn load_contracts(client: &ApiClient) -> Result<Vec<ListItem>, Box<dyn std::error::Error + Send + Sync>> {
     let result = client.list_contracts().await?;
diff --git a/makima/src/daemon/api/chain.rs b/makima/src/daemon/api/chain.rs
new file mode 100644
index 0000000..7f7826f
--- /dev/null
+++ b/makima/src/daemon/api/chain.rs
@@ -0,0 +1,52 @@
+//! Chain API methods.
+
+use uuid::Uuid;
+
+use super::client::{ApiClient, ApiError};
+use super::supervisor::JsonValue;
+use crate::db::models::CreateChainRequest;
+
+impl ApiClient {
+    /// Create a new chain with contracts.
+    pub async fn create_chain(&self, req: CreateChainRequest) -> Result<JsonValue, ApiError> {
+        self.post("/api/v1/chains", &req).await
+    }
+
+    /// List all chains for the authenticated user.
+    pub async fn list_chains(
+        &self,
+        status: Option<&str>,
+        limit: i32,
+    ) -> Result<JsonValue, ApiError> {
+        let mut params = Vec::new();
+        if let Some(s) = status {
+            params.push(format!("status={}", s));
+        }
+        params.push(format!("limit={}", limit));
+        let query_string = format!("?{}", params.join("&"));
+        self.get(&format!("/api/v1/chains{}", query_string)).await
+    }
+
+    /// Get a chain by ID.
+    pub async fn get_chain(&self, chain_id: Uuid) -> Result<JsonValue, ApiError> {
+        self.get(&format!("/api/v1/chains/{}", chain_id)).await
+    }
+
+    /// Get contracts in a chain.
+    pub async fn get_chain_contracts(&self, chain_id: Uuid) -> Result<JsonValue, ApiError> {
+        self.get(&format!("/api/v1/chains/{}/contracts", chain_id))
+            .await
+    }
+
+    /// Get chain DAG structure for visualization.
+    pub async fn get_chain_graph(&self, chain_id: Uuid) -> Result<JsonValue, ApiError> {
+        self.get(&format!("/api/v1/chains/{}/graph", chain_id))
+            .await
+    }
+
+    /// Archive a chain.
+    pub async fn archive_chain(&self, chain_id: Uuid) -> Result<JsonValue, ApiError> {
+        self.delete_with_response(&format!("/api/v1/chains/{}", chain_id))
+            .await
+    }
+}
diff --git a/makima/src/daemon/api/client.rs b/makima/src/daemon/api/client.rs
index 4ba4778..dbf3101 100644
--- a/makima/src/daemon/api/client.rs
+++ b/makima/src/daemon/api/client.rs
@@ -276,6 +276,48 @@ impl ApiClient {
         Err(last_error.unwrap())
     }
 
+    /// Make a DELETE request with response and retry.
+    pub async fn delete_with_response<T: DeserializeOwned>(&self, path: &str) -> Result<T, ApiError> {
+        let url = format!("{}{}", self.base_url, path);
+        let mut last_error = None;
+
+        for attempt in 0..MAX_RETRIES {
+            if attempt > 0 {
+                tokio::time::sleep(Self::backoff_delay(attempt - 1)).await;
+            }
+
+            let result = self.client
+                .delete(&url)
+                .header("X-Makima-Tool-Key", &self.api_key)
+                .header("X-Makima-API-Key", &self.api_key)
+                .send()
+                .await;
+
+            match result {
+                Ok(response) => {
+                    match self.handle_response(response).await {
+                        Ok(value) => return Ok(value),
+                        Err(e) if Self::is_retryable(&e) && attempt < MAX_RETRIES - 1 => {
+                            last_error = Some(e);
+                            continue;
+                        }
+                        Err(e) => return Err(e),
+                    }
+                }
+                Err(e) => {
+                    let error = ApiError::Request(e);
+                    if Self::is_retryable(&error) && attempt < MAX_RETRIES - 1 {
+                        last_error = Some(error);
+                        continue;
+                    }
+                    return Err(error);
+                }
+            }
+        }
+
+        Err(last_error.unwrap())
+    }
+
     /// Handle API response.
     async fn handle_response<T: DeserializeOwned>(
         &self,
diff --git a/makima/src/daemon/api/mod.rs b/makima/src/daemon/api/mod.rs
index 49d80e0..7868907 100644
--- a/makima/src/daemon/api/mod.rs
+++ b/makima/src/daemon/api/mod.rs
@@ -1,5 +1,6 @@
 //! HTTP API client for makima CLI commands.
 
+pub mod chain;
 pub mod client;
 pub mod contract;
 pub mod supervisor;
diff --git a/makima/src/daemon/chain/dag.rs b/makima/src/daemon/chain/dag.rs
new file mode 100644
index 0000000..7ba5904
--- /dev/null
+++ b/makima/src/daemon/chain/dag.rs
@@ -0,0 +1,450 @@
+//! DAG validation and traversal for chain contracts.
+//!
+//! Provides cycle detection and topological sorting for contract dependencies.
+
+use std::collections::{HashMap, HashSet, VecDeque};
+use thiserror::Error;
+
+use super::parser::ChainDefinition;
+
+/// Error type for DAG operations.
+#[derive(Error, Debug)]
+pub enum DagError {
+    #[error("Cycle detected in dependency graph: {0}")]
+    CycleDetected(String),
+
+    #[error("Unknown contract in dependency: {0}")]
+    UnknownContract(String),
+}
+
+/// Validates that the chain definition forms a valid DAG (no cycles).
+///
+/// Uses depth-first search with color marking to detect cycles.
+/// Returns Ok(()) if valid, or an error describing the cycle.
+pub fn validate_dag(chain: &ChainDefinition) -> Result<(), DagError> {
+    // Build adjacency list from contract dependencies
+    let mut adjacency: HashMap<&str, Vec<&str>> = HashMap::new();
+    let contract_names: HashSet<&str> = chain.contracts.iter().map(|c| c.name.as_str()).collect();
+
+    for contract in &chain.contracts {
+        let deps: Vec<&str> = contract
+            .depends_on
+            .as_ref()
+            .map(|d| d.iter().map(|s| s.as_str()).collect())
+            .unwrap_or_default();
+
+        // Validate all dependencies exist
+        for dep in &deps {
+            if !contract_names.contains(dep) {
+                return Err(DagError::UnknownContract(format!(
+                    "Contract '{}' depends on unknown contract '{}'",
+                    contract.name, dep
+                )));
+            }
+        }
+
+        adjacency.insert(contract.name.as_str(), deps);
+    }
+
+    // Color-based DFS for cycle detection
+    // White (0): not visited, Gray (1): in progress, Black (2): completed
+    let mut color: HashMap<&str, u8> = HashMap::new();
+    for name in &contract_names {
+        color.insert(name, 0);
+    }
+
+    // Track path for cycle reporting
+    fn dfs<'a>(
+        node: &'a str,
+        adjacency: &HashMap<&'a str, Vec<&'a str>>,
+        color: &mut HashMap<&'a str, u8>,
+        path: &mut Vec<&'a str>,
+    ) -> Result<(), DagError> {
+        color.insert(node, 1); // Mark as in-progress
+        path.push(node);
+
+        if let Some(deps) = adjacency.get(node) {
+            for dep in deps {
+                match color.get(dep) {
+                    Some(1) => {
+                        // Found cycle - dep is in current path
+                        let cycle_start = path.iter().position(|&n| n == *dep).unwrap();
+                        let cycle: Vec<_> = path[cycle_start..].to_vec();
+                        return Err(DagError::CycleDetected(format!(
+                            "{} -> {}",
+                            cycle.join(" -> "),
+                            dep
+                        )));
+                    }
+                    Some(0) => {
+                        // Not visited - recurse
+                        dfs(dep, adjacency, color, path)?;
+                    }
+                    _ => {
+                        // Already completed - skip
+                    }
+                }
+            }
+        }
+
+        color.insert(node, 2); // Mark as completed
+        path.pop();
+        Ok(())
+    }
+
+    // Run DFS from each unvisited node
+    for name in &contract_names {
+        if color.get(name) == Some(&0) {
+            let mut path = Vec::new();
+            dfs(name, &adjacency, &mut color, &mut path)?;
+        }
+    }
+
+    Ok(())
+}
+
+/// Returns contracts in topological order (dependencies before dependents).
+///
+/// Uses Kahn's algorithm for topological sorting.
+pub fn topological_sort(chain: &ChainDefinition) -> Result<Vec<&str>, DagError> {
+    // Validate first
+    validate_dag(chain)?;
+
+    // Build in-degree map and adjacency list
+    let mut in_degree: HashMap<&str, usize> = HashMap::new();
+    let mut dependents: HashMap<&str, Vec<&str>> = HashMap::new();
+
+    for contract in &chain.contracts {
+        in_degree.entry(contract.name.as_str()).or_insert(0);
+        dependents.entry(contract.name.as_str()).or_default();
+
+        if let Some(deps) = &contract.depends_on {
+            for dep in deps {
+                *in_degree.entry(contract.name.as_str()).or_insert(0) += 1;
+                dependents
+                    .entry(dep.as_str())
+                    .or_default()
+                    .push(contract.name.as_str());
+            }
+        }
+    }
+
+    // Kahn's algorithm
+    let mut queue: VecDeque<&str> = VecDeque::new();
+    let mut result: Vec<&str> = Vec::new();
+
+    // Start with nodes that have no dependencies
+    for (name, &degree) in &in_degree {
+        if degree == 0 {
+            queue.push_back(name);
+        }
+    }
+
+    while let Some(node) = queue.pop_front() {
+        result.push(node);
+
+        if let Some(deps) = dependents.get(node) {
+            for dep in deps {
+                if let Some(degree) = in_degree.get_mut(dep) {
+                    *degree -= 1;
+                    if *degree == 0 {
+                        queue.push_back(dep);
+                    }
+                }
+            }
+        }
+    }
+
+    Ok(result)
+}
+
+/// Returns contracts that are ready to run (have no unmet dependencies).
+///
+/// Takes a set of completed contract names and returns contracts that
+/// can now be started.
+pub fn get_ready_contracts<'a>(
+    chain: &'a ChainDefinition,
+    completed: &HashSet<&str>,
+) -> Vec<&'a str> {
+    chain
+        .contracts
+        .iter()
+        .filter(|c| {
+            // Already completed? Skip
+            if completed.contains(c.name.as_str()) {
+                return false;
+            }
+
+            // Check if all dependencies are met
+            match &c.depends_on {
+                None => true, // No dependencies
+                Some(deps) => deps.iter().all(|d| completed.contains(d.as_str())),
+            }
+        })
+        .map(|c| c.name.as_str())
+        .collect()
+}
+
+/// Get the depth of each contract in the DAG (for layout purposes).
+///
+/// Root nodes (no dependencies) have depth 0.
+/// Each dependent has depth = max(dependency depths) + 1.
+pub fn get_contract_depths(chain: &ChainDefinition) -> HashMap<&str, usize> {
+    let mut depths: HashMap<&str, usize> = HashMap::new();
+
+    // Multiple passes to handle dependencies
+    let max_iterations = chain.contracts.len();
+    for _ in 0..max_iterations {
+        let mut changed = false;
+
+        for contract in &chain.contracts {
+            let new_depth = match &contract.depends_on {
+                None => 0,
+                Some(deps) => {
+                    if deps.iter().all(|d| depths.contains_key(d.as_str())) {
+                        deps.iter()
+                            .filter_map(|d| depths.get(d.as_str()))
+                            .max()
+                            .copied()
+                            .unwrap_or(0)
+                            + 1
+                    } else {
+                        continue; // Dependencies not yet computed
+                    }
+                }
+            };
+
+            if depths.get(contract.name.as_str()) != Some(&new_depth) {
+                depths.insert(contract.name.as_str(), new_depth);
+                changed = true;
+            }
+        }
+
+        if !changed {
+            break;
+        }
+    }
+
+    depths
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::daemon::chain::parser::parse_chain_yaml;
+
+    #[test]
+    fn test_valid_dag() {
+        let yaml = r#"
+name: Valid DAG
+contracts:
+  - name: A
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+  - name: C
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do C"
+  - name: D
+    depends_on: [B, C]
+    tasks:
+      - name: Task
+        plan: "Do D"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        assert!(validate_dag(&chain).is_ok());
+    }
+
+    #[test]
+    fn test_simple_cycle() {
+        let yaml = r#"
+name: Simple Cycle
+contracts:
+  - name: A
+    depends_on: [B]
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let result = validate_dag(&chain);
+        assert!(result.is_err());
+        assert!(result.unwrap_err().to_string().contains("Cycle detected"));
+    }
+
+    #[test]
+    fn test_longer_cycle() {
+        let yaml = r#"
+name: Longer Cycle
+contracts:
+  - name: A
+    depends_on: [C]
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+  - name: C
+    depends_on: [B]
+    tasks:
+      - name: Task
+        plan: "Do C"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let result = validate_dag(&chain);
+        assert!(result.is_err());
+        assert!(result.unwrap_err().to_string().contains("Cycle detected"));
+    }
+
+    #[test]
+    fn test_topological_sort() {
+        let yaml = r#"
+name: Topo Test
+contracts:
+  - name: A
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+  - name: C
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do C"
+  - name: D
+    depends_on: [B, C]
+    tasks:
+      - name: Task
+        plan: "Do D"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let sorted = topological_sort(&chain).unwrap();
+
+        // A must come before B, C; B and C must come before D
+        let pos_a = sorted.iter().position(|&n| n == "A").unwrap();
+        let pos_b = sorted.iter().position(|&n| n == "B").unwrap();
+        let pos_c = sorted.iter().position(|&n| n == "C").unwrap();
+        let pos_d = sorted.iter().position(|&n| n == "D").unwrap();
+
+        assert!(pos_a < pos_b);
+        assert!(pos_a < pos_c);
+        assert!(pos_b < pos_d);
+        assert!(pos_c < pos_d);
+    }
+
+    #[test]
+    fn test_get_ready_contracts() {
+        let yaml = r#"
+name: Ready Test
+contracts:
+  - name: A
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+  - name: C
+    tasks:
+      - name: Task
+        plan: "Do C"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+
+        // Initially A and C are ready (no dependencies)
+        let completed = HashSet::new();
+        let mut ready = get_ready_contracts(&chain, &completed);
+        ready.sort();
+        assert_eq!(ready, vec!["A", "C"]);
+
+        // After A completes, B becomes ready
+        let mut completed = HashSet::new();
+        completed.insert("A");
+        let ready = get_ready_contracts(&chain, &completed);
+        assert!(ready.contains(&"B"));
+        assert!(ready.contains(&"C")); // C still ready if not started
+    }
+
+    #[test]
+    fn test_get_contract_depths() {
+        let yaml = r#"
+name: Depth Test
+contracts:
+  - name: A
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+  - name: C
+    depends_on: [B]
+    tasks:
+      - name: Task
+        plan: "Do C"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let depths = get_contract_depths(&chain);
+
+        assert_eq!(depths.get("A"), Some(&0));
+        assert_eq!(depths.get("B"), Some(&1));
+        assert_eq!(depths.get("C"), Some(&2));
+    }
+
+    #[test]
+    fn test_diamond_dependency_depths() {
+        let yaml = r#"
+name: Diamond Test
+contracts:
+  - name: A
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+  - name: C
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do C"
+  - name: D
+    depends_on: [B, C]
+    tasks:
+      - name: Task
+        plan: "Do D"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let depths = get_contract_depths(&chain);
+
+        assert_eq!(depths.get("A"), Some(&0));
+        assert_eq!(depths.get("B"), Some(&1));
+        assert_eq!(depths.get("C"), Some(&1));
+        assert_eq!(depths.get("D"), Some(&2));
+    }
+}
diff --git a/makima/src/daemon/chain/mod.rs b/makima/src/daemon/chain/mod.rs
new file mode 100644
index 0000000..5588a27
--- /dev/null
+++ b/makima/src/daemon/chain/mod.rs
@@ -0,0 +1,13 @@
+//! Chain module - DAG-based multi-contract orchestration.
+//!
+//! Chains are directed acyclic graphs (DAGs) of contracts that work together
+//! to achieve a larger goal. Each contract can depend on others, and contracts
+//! run in parallel when no dependencies exist.
+
+pub mod dag;
+pub mod parser;
+pub mod runner;
+
+pub use dag::{validate_dag, DagError};
+pub use parser::{parse_chain_file, ChainDefinition, ParseError};
+pub use runner::{ChainRunner, RunnerError};
diff --git a/makima/src/daemon/chain/parser.rs b/makima/src/daemon/chain/parser.rs
new file mode 100644
index 0000000..0f16710
--- /dev/null
+++ b/makima/src/daemon/chain/parser.rs
@@ -0,0 +1,392 @@
+//! Chain YAML parser.
+//!
+//! Parses chain definition files in YAML format into structured data
+//! that can be used to create chains and contracts.
+
+use serde::{Deserialize, Serialize};
+use std::path::Path;
+use thiserror::Error;
+
+/// Error type for chain parsing operations.
+#[derive(Error, Debug)]
+pub enum ParseError {
+    #[error("Failed to read chain file: {0}")]
+    IoError(#[from] std::io::Error),
+
+    #[error("Failed to parse YAML: {0}")]
+    YamlError(#[from] serde_yaml::Error),
+
+    #[error("Validation error: {0}")]
+    ValidationError(String),
+}
+
+/// Chain definition parsed from YAML.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ChainDefinition {
+    /// Name of the chain
+    pub name: String,
+    /// Optional description
+    pub description: Option<String>,
+    /// Repository URL (optional - contracts may have their own repos)
+    #[serde(alias = "repo")]
+    pub repository_url: Option<String>,
+    /// Local path for repository
+    pub local_path: Option<String>,
+    /// Contracts in this chain
+    pub contracts: Vec<ContractDefinition>,
+    /// Loop configuration
+    #[serde(rename = "loop")]
+    pub loop_config: Option<LoopConfig>,
+}
+
+/// Contract definition within a chain.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ContractDefinition {
+    /// Name of the contract
+    pub name: String,
+    /// Optional description
+    pub description: Option<String>,
+    /// Contract type (defaults to "simple")
+    #[serde(rename = "type", default = "default_contract_type")]
+    pub contract_type: String,
+    /// Phases for this contract
+    pub phases: Option<Vec<String>>,
+    /// Names of contracts this depends on (DAG edges)
+    pub depends_on: Option<Vec<String>>,
+    /// Tasks to create in this contract
+    pub tasks: Option<Vec<TaskDefinition>>,
+    /// Deliverables for this contract
+    pub deliverables: Option<Vec<DeliverableDefinition>>,
+}
+
+fn default_contract_type() -> String {
+    "simple".to_string()
+}
+
+/// Task definition within a contract.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct TaskDefinition {
+    /// Name of the task
+    pub name: String,
+    /// Plan/instructions for the task
+    pub plan: String,
+}
+
+/// Deliverable definition within a contract.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct DeliverableDefinition {
+    /// Unique identifier for the deliverable
+    pub id: String,
+    /// Name of the deliverable
+    pub name: String,
+    /// Priority level (defaults to "required")
+    #[serde(default = "default_priority")]
+    pub priority: String,
+}
+
+fn default_priority() -> String {
+    "required".to_string()
+}
+
+/// Loop configuration for chain iteration.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct LoopConfig {
+    /// Whether loop is enabled
+    #[serde(default)]
+    pub enabled: bool,
+    /// Maximum number of iterations
+    #[serde(default = "default_max_iterations")]
+    pub max_iterations: i32,
+    /// Progress check prompt/criteria
+    pub progress_check: Option<String>,
+}
+
+fn default_max_iterations() -> i32 {
+    10
+}
+
+impl ChainDefinition {
+    /// Validate the chain definition.
+    pub fn validate(&self) -> Result<(), ParseError> {
+        // Check for empty name
+        if self.name.trim().is_empty() {
+            return Err(ParseError::ValidationError(
+                "Chain name cannot be empty".to_string(),
+            ));
+        }
+
+        // Check for at least one contract
+        if self.contracts.is_empty() {
+            return Err(ParseError::ValidationError(
+                "Chain must have at least one contract".to_string(),
+            ));
+        }
+
+        // Collect all contract names for dependency validation
+        let contract_names: std::collections::HashSet<_> =
+            self.contracts.iter().map(|c| c.name.as_str()).collect();
+
+        // Check for duplicate contract names
+        if contract_names.len() != self.contracts.len() {
+            return Err(ParseError::ValidationError(
+                "Duplicate contract names found".to_string(),
+            ));
+        }
+
+        // Validate each contract
+        for contract in &self.contracts {
+            contract.validate(&contract_names)?;
+        }
+
+        Ok(())
+    }
+}
+
+impl ContractDefinition {
+    /// Validate the contract definition.
+    pub fn validate(
+        &self,
+        valid_contract_names: &std::collections::HashSet<&str>,
+    ) -> Result<(), ParseError> {
+        // Check for empty name
+        if self.name.trim().is_empty() {
+            return Err(ParseError::ValidationError(
+                "Contract name cannot be empty".to_string(),
+            ));
+        }
+
+        // Validate dependencies exist
+        if let Some(deps) = &self.depends_on {
+            for dep in deps {
+                if !valid_contract_names.contains(dep.as_str()) {
+                    return Err(ParseError::ValidationError(format!(
+                        "Contract '{}' depends on unknown contract '{}'",
+                        self.name, dep
+                    )));
+                }
+                // Self-dependency check
+                if dep == &self.name {
+                    return Err(ParseError::ValidationError(format!(
+                        "Contract '{}' cannot depend on itself",
+                        self.name
+                    )));
+                }
+            }
+        }
+
+        // Validate tasks
+        if let Some(tasks) = &self.tasks {
+            for task in tasks {
+                if task.name.trim().is_empty() {
+                    return Err(ParseError::ValidationError(format!(
+                        "Task name cannot be empty in contract '{}'",
+                        self.name
+                    )));
+                }
+                if task.plan.trim().is_empty() {
+                    return Err(ParseError::ValidationError(format!(
+                        "Task '{}' in contract '{}' has empty plan",
+                        task.name, self.name
+                    )));
+                }
+            }
+        }
+
+        Ok(())
+    }
+}
+
+/// Parse a chain definition from a YAML file.
+pub fn parse_chain_file<P: AsRef<Path>>(path: P) -> Result<ChainDefinition, ParseError> {
+    let content = std::fs::read_to_string(path)?;
+    parse_chain_yaml(&content)
+}
+
+/// Parse a chain definition from a YAML string.
+pub fn parse_chain_yaml(yaml: &str) -> Result<ChainDefinition, ParseError> {
+    let definition: ChainDefinition = serde_yaml::from_str(yaml)?;
+    definition.validate()?;
+    Ok(definition)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse_simple_chain() {
+        let yaml = r#"
+name: Test Chain
+description: A test chain
+contracts:
+  - name: Research
+    type: simple
+    tasks:
+      - name: Analyze
+        plan: "Analyze the codebase"
+  - name: Implement
+    type: simple
+    depends_on: [Research]
+    tasks:
+      - name: Build
+        plan: "Build the feature"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        assert_eq!(chain.name, "Test Chain");
+        assert_eq!(chain.contracts.len(), 2);
+        assert_eq!(chain.contracts[0].name, "Research");
+        assert_eq!(chain.contracts[1].name, "Implement");
+        assert_eq!(
+            chain.contracts[1].depends_on,
+            Some(vec!["Research".to_string()])
+        );
+    }
+
+    #[test]
+    fn test_parse_chain_with_loop() {
+        let yaml = r#"
+name: Iterative Chain
+contracts:
+  - name: Phase1
+    tasks:
+      - name: Task1
+        plan: "Do something"
+loop:
+  enabled: true
+  max_iterations: 5
+  progress_check: "Check if goals are met"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        assert!(chain.loop_config.is_some());
+        let loop_config = chain.loop_config.unwrap();
+        assert!(loop_config.enabled);
+        assert_eq!(loop_config.max_iterations, 5);
+    }
+
+    #[test]
+    fn test_parse_chain_with_deliverables() {
+        let yaml = r#"
+name: Feature Chain
+contracts:
+  - name: Research
+    tasks:
+      - name: Survey
+        plan: "Survey existing code"
+    deliverables:
+      - id: analysis
+        name: Codebase Analysis
+        priority: required
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let deliverables = chain.contracts[0].deliverables.as_ref().unwrap();
+        assert_eq!(deliverables.len(), 1);
+        assert_eq!(deliverables[0].id, "analysis");
+    }
+
+    #[test]
+    fn test_validation_empty_name() {
+        let yaml = r#"
+name: ""
+contracts:
+  - name: Phase1
+    tasks:
+      - name: Task1
+        plan: "Do something"
+"#;
+        let result = parse_chain_yaml(yaml);
+        assert!(result.is_err());
+        assert!(result
+            .unwrap_err()
+            .to_string()
+            .contains("name cannot be empty"));
+    }
+
+    #[test]
+    fn test_validation_no_contracts() {
+        let yaml = r#"
+name: Empty Chain
+contracts: []
+"#;
+        let result = parse_chain_yaml(yaml);
+        assert!(result.is_err());
+        assert!(result
+            .unwrap_err()
+            .to_string()
+            .contains("at least one contract"));
+    }
+
+    #[test]
+    fn test_validation_unknown_dependency() {
+        let yaml = r#"
+name: Bad Chain
+contracts:
+  - name: Phase1
+    depends_on: [NonExistent]
+    tasks:
+      - name: Task1
+        plan: "Do something"
+"#;
+        let result = parse_chain_yaml(yaml);
+        assert!(result.is_err());
+        assert!(result.unwrap_err().to_string().contains("unknown contract"));
+    }
+
+    #[test]
+    fn test_validation_self_dependency() {
+        let yaml = r#"
+name: Self Ref Chain
+contracts:
+  - name: Phase1
+    depends_on: [Phase1]
+    tasks:
+      - name: Task1
+        plan: "Do something"
+"#;
+        let result = parse_chain_yaml(yaml);
+        assert!(result.is_err());
+        assert!(result
+            .unwrap_err()
+            .to_string()
+            .contains("cannot depend on itself"));
+    }
+
+    #[test]
+    fn test_validation_duplicate_names() {
+        let yaml = r#"
+name: Dup Chain
+contracts:
+  - name: Phase1
+    tasks:
+      - name: Task1
+        plan: "Do something"
+  - name: Phase1
+    tasks:
+      - name: Task2
+        plan: "Do another thing"
+"#;
+        let result = parse_chain_yaml(yaml);
+        assert!(result.is_err());
+        assert!(result
+            .unwrap_err()
+            .to_string()
+            .contains("Duplicate contract names"));
+    }
+
+    #[test]
+    fn test_repo_alias() {
+        let yaml = r#"
+name: Repo Chain
+repo: https://github.com/user/project
+contracts:
+  - name: Phase1
+    tasks:
+      - name: Task1
+        plan: "Work on repo"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        assert_eq!(
+            chain.repository_url,
+            Some("https://github.com/user/project".to_string())
+        );
+    }
+}
diff --git a/makima/src/daemon/chain/runner.rs b/makima/src/daemon/chain/runner.rs
new file mode 100644
index 0000000..9c6f6b4
--- /dev/null
+++ b/makima/src/daemon/chain/runner.rs
@@ -0,0 +1,364 @@
+//! Chain runner - creates and orchestrates contracts from chain definitions.
+//!
+//! Handles the lifecycle of a chain:
+//! 1. Parse chain definition
+//! 2. Validate DAG
+//! 3. Create chain record
+//! 4. Create contracts in dependency order
+//! 5. Monitor and trigger dependent contracts
+
+use std::collections::HashMap;
+use std::path::Path;
+use thiserror::Error;
+
+use super::dag::{topological_sort, validate_dag, DagError};
+use super::parser::{parse_chain_file, ChainDefinition, ParseError};
+use crate::db::models::{
+    CreateChainContractRequest, CreateChainDeliverableRequest, CreateChainRequest,
+    CreateChainTaskRequest,
+};
+
+/// Error type for chain runner operations.
+#[derive(Error, Debug)]
+pub enum RunnerError {
+    #[error("Parse error: {0}")]
+    Parse(#[from] ParseError),
+
+    #[error("DAG error: {0}")]
+    Dag(#[from] DagError),
+
+    #[error("API error: {0}")]
+    Api(String),
+
+    #[error("Contract creation failed: {0}")]
+    ContractCreation(String),
+}
+
+/// Chain runner for creating and managing chains.
+pub struct ChainRunner {
+    /// Base API URL
+    api_url: String,
+    /// API key for authentication
+    api_key: String,
+}
+
+impl ChainRunner {
+    /// Create a new chain runner.
+    pub fn new(api_url: String, api_key: String) -> Self {
+        Self { api_url, api_key }
+    }
+
+    /// Load and validate a chain from a YAML file.
+    pub fn load_chain<P: AsRef<Path>>(&self, path: P) -> Result<ChainDefinition, RunnerError> {
+        let chain = parse_chain_file(path)?;
+        validate_dag(&chain)?;
+        Ok(chain)
+    }
+
+    /// Convert a chain definition to a CreateChainRequest for API submission.
+    pub fn to_create_request(&self, chain: &ChainDefinition) -> CreateChainRequest {
+        let contracts: Vec<CreateChainContractRequest> = chain
+            .contracts
+            .iter()
+            .map(|c| CreateChainContractRequest {
+                name: c.name.clone(),
+                description: c.description.clone(),
+                contract_type: Some(c.contract_type.clone()),
+                initial_phase: None,
+                phases: c.phases.clone(),
+                depends_on: c.depends_on.clone(),
+                tasks: c.tasks.as_ref().map(|tasks| {
+                    tasks
+                        .iter()
+                        .map(|t| CreateChainTaskRequest {
+                            name: t.name.clone(),
+                            plan: t.plan.clone(),
+                        })
+                        .collect()
+                }),
+                deliverables: c.deliverables.as_ref().map(|dels| {
+                    dels.iter()
+                        .map(|d| CreateChainDeliverableRequest {
+                            id: d.id.clone(),
+                            name: d.name.clone(),
+                            priority: Some(d.priority.clone()),
+                        })
+                        .collect()
+                }),
+                editor_x: None,
+                editor_y: None,
+            })
+            .collect();
+
+        let (loop_enabled, loop_max_iterations, loop_progress_check) =
+            match &chain.loop_config {
+                Some(lc) => (
+                    Some(lc.enabled),
+                    Some(lc.max_iterations),
+                    lc.progress_check.clone(),
+                ),
+                None => (None, None, None),
+            };
+
+        CreateChainRequest {
+            name: chain.name.clone(),
+            description: chain.description.clone(),
+            repository_url: chain.repository_url.clone(),
+            local_path: chain.local_path.clone(),
+            loop_enabled,
+            loop_max_iterations,
+            loop_progress_check,
+            contracts: Some(contracts),
+        }
+    }
+
+    /// Get contracts in topological order (for display/debugging).
+    pub fn get_execution_order<'a>(
+        &self,
+        chain: &'a ChainDefinition,
+    ) -> Result<Vec<&'a str>, RunnerError> {
+        Ok(topological_sort(chain)?)
+    }
+
+    /// Generate ASCII visualization of the chain DAG.
+    pub fn visualize_dag(&self, chain: &ChainDefinition) -> String {
+        use super::dag::get_contract_depths;
+
+        let depths = get_contract_depths(chain);
+        let mut lines: Vec<String> = vec![];
+
+        lines.push(format!("Chain: {}", chain.name));
+        if let Some(desc) = &chain.description {
+            lines.push(format!("  {}", desc));
+        }
+        lines.push(String::new());
+
+        // Group contracts by depth
+        let mut by_depth: HashMap<usize, Vec<&str>> = HashMap::new();
+        for contract in &chain.contracts {
+            let depth = depths.get(contract.name.as_str()).copied().unwrap_or(0);
+            by_depth.entry(depth).or_default().push(&contract.name);
+        }
+
+        // Find max depth
+        let max_depth = by_depth.keys().max().copied().unwrap_or(0);
+
+        // Build visualization
+        for depth in 0..=max_depth {
+            if let Some(contracts) = by_depth.get(&depth) {
+                let contract_strs: Vec<String> = contracts
+                    .iter()
+                    .map(|name| format!("[{}]", name))
+                    .collect();
+
+                let indent = "  ".repeat(depth);
+                lines.push(format!("{}{}", indent, contract_strs.join("  ")));
+
+                // Draw arrows to next level
+                if depth < max_depth {
+                    if let Some(next_contracts) = by_depth.get(&(depth + 1)) {
+                        // Find which contracts connect to the next level
+                        for next in next_contracts {
+                            let next_contract = chain
+                                .contracts
+                                .iter()
+                                .find(|c| c.name.as_str() == *next)
+                                .unwrap();
+
+                            if let Some(deps) = &next_contract.depends_on {
+                                for dep in deps {
+                                    if contracts.contains(&dep.as_str()) {
+                                        let arrow_indent = "  ".repeat(depth);
+                                        lines.push(format!("{}  │", arrow_indent));
+                                        lines.push(format!("{}  ▼", arrow_indent));
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        lines.join("\n")
+    }
+}
+
+/// Compute editor positions for contracts based on DAG layout.
+///
+/// Returns a map of contract name to (x, y) positions suitable for
+/// the GUI editor.
+pub fn compute_editor_positions(chain: &ChainDefinition) -> HashMap<String, (f64, f64)> {
+    use super::dag::get_contract_depths;
+
+    let depths = get_contract_depths(chain);
+    let mut positions: HashMap<String, (f64, f64)> = HashMap::new();
+
+    // Group by depth
+    let mut by_depth: HashMap<usize, Vec<&str>> = HashMap::new();
+    for contract in &chain.contracts {
+        let depth = depths.get(contract.name.as_str()).copied().unwrap_or(0);
+        by_depth.entry(depth).or_default().push(&contract.name);
+    }
+
+    // Compute positions: x based on depth, y based on index within depth
+    let x_spacing = 250.0;
+    let y_spacing = 150.0;
+
+    for (depth, contracts) in &by_depth {
+        let x = (*depth as f64) * x_spacing + 100.0;
+        for (i, name) in contracts.iter().enumerate() {
+            let y = (i as f64) * y_spacing + 100.0;
+            positions.insert(name.to_string(), (x, y));
+        }
+    }
+
+    positions
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::daemon::chain::parser::parse_chain_yaml;
+
+    #[test]
+    fn test_to_create_request() {
+        let yaml = r#"
+name: Test Chain
+description: A test chain
+repo: https://github.com/test/repo
+contracts:
+  - name: Research
+    type: simple
+    phases: [plan, execute]
+    tasks:
+      - name: Analyze
+        plan: "Analyze the codebase"
+    deliverables:
+      - id: analysis
+        name: Analysis Doc
+        priority: required
+  - name: Implement
+    depends_on: [Research]
+    tasks:
+      - name: Build
+        plan: "Build the feature"
+loop:
+  enabled: true
+  max_iterations: 5
+  progress_check: "Check completion"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let runner = ChainRunner::new("http://localhost".to_string(), "key".to_string());
+        let request = runner.to_create_request(&chain);
+
+        assert_eq!(request.name, "Test Chain");
+        assert_eq!(request.description, Some("A test chain".to_string()));
+        assert_eq!(
+            request.repository_url,
+            Some("https://github.com/test/repo".to_string())
+        );
+        assert_eq!(request.loop_enabled, Some(true));
+        assert_eq!(request.loop_max_iterations, Some(5));
+
+        let contracts = request.contracts.unwrap();
+        assert_eq!(contracts.len(), 2);
+        assert_eq!(contracts[0].name, "Research");
+        assert_eq!(contracts[0].phases, Some(vec!["plan".to_string(), "execute".to_string()]));
+        assert_eq!(
+            contracts[1].depends_on,
+            Some(vec!["Research".to_string()])
+        );
+    }
+
+    #[test]
+    fn test_get_execution_order() {
+        let yaml = r#"
+name: Order Test
+contracts:
+  - name: C
+    depends_on: [B]
+    tasks:
+      - name: Task
+        plan: "Do C"
+  - name: A
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let runner = ChainRunner::new("http://localhost".to_string(), "key".to_string());
+        let order = runner.get_execution_order(&chain).unwrap();
+
+        let pos_a = order.iter().position(|&n| n == "A").unwrap();
+        let pos_b = order.iter().position(|&n| n == "B").unwrap();
+        let pos_c = order.iter().position(|&n| n == "C").unwrap();
+
+        assert!(pos_a < pos_b);
+        assert!(pos_b < pos_c);
+    }
+
+    #[test]
+    fn test_visualize_dag() {
+        let yaml = r#"
+name: Visual Test
+description: Test visualization
+contracts:
+  - name: A
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let runner = ChainRunner::new("http://localhost".to_string(), "key".to_string());
+        let viz = runner.visualize_dag(&chain);
+
+        assert!(viz.contains("Chain: Visual Test"));
+        assert!(viz.contains("[A]"));
+        assert!(viz.contains("[B]"));
+    }
+
+    #[test]
+    fn test_compute_editor_positions() {
+        let yaml = r#"
+name: Position Test
+contracts:
+  - name: A
+    tasks:
+      - name: Task
+        plan: "Do A"
+  - name: B
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do B"
+  - name: C
+    depends_on: [A]
+    tasks:
+      - name: Task
+        plan: "Do C"
+"#;
+        let chain = parse_chain_yaml(yaml).unwrap();
+        let positions = compute_editor_positions(&chain);
+
+        // A should be at depth 0 (x = 100)
+        let (a_x, _) = positions.get("A").unwrap();
+        assert_eq!(*a_x, 100.0);
+
+        // B and C should be at depth 1 (x = 350)
+        let (b_x, _) = positions.get("B").unwrap();
+        let (c_x, _) = positions.get("C").unwrap();
+        assert_eq!(*b_x, 350.0);
+        assert_eq!(*c_x, 350.0);
+    }
+}
diff --git a/makima/src/daemon/cli/chain.rs b/makima/src/daemon/cli/chain.rs
new file mode 100644
index 0000000..1d7c167
--- /dev/null
+++ b/makima/src/daemon/cli/chain.rs
@@ -0,0 +1,107 @@
+//! Chain CLI commands for multi-contract orchestration.
+//!
+//! Provides commands for creating, managing, and visualizing chains
+//! (DAGs of contracts).
+
+use clap::Args;
+use std::path::PathBuf;
+use uuid::Uuid;
+
+/// Common arguments for chain commands requiring API access.
+#[derive(Args, Debug, Clone)]
+pub struct ChainArgs {
+    /// API URL
+    #[arg(long, env = "MAKIMA_API_URL", default_value = "https://api.makima.jp", global = true)]
+    pub api_url: String,
+
+    /// API key for authentication
+    #[arg(long, env = "MAKIMA_API_KEY", global = true)]
+    pub api_key: String,
+}
+
+/// Arguments for the `run` command (create chain from YAML file).
+#[derive(Args, Debug)]
+pub struct RunArgs {
+    #[command(flatten)]
+    pub common: ChainArgs,
+
+    /// Path to the chain YAML file
+    pub file: PathBuf,
+
+    /// Don't actually create the chain, just validate and show what would be created
+    #[arg(long)]
+    pub dry_run: bool,
+}
+
+/// Arguments for the `status` command.
+#[derive(Args, Debug)]
+pub struct StatusArgs {
+    #[command(flatten)]
+    pub common: ChainArgs,
+
+    /// Chain ID
+    pub chain_id: Uuid,
+}
+
+/// Arguments for the `list` command.
+#[derive(Args, Debug)]
+pub struct ListArgs {
+    #[command(flatten)]
+    pub common: ChainArgs,
+
+    /// Filter by status (active, completed, archived)
+    #[arg(long)]
+    pub status: Option<String>,
+
+    /// Limit number of results
+    #[arg(long, default_value = "50")]
+    pub limit: i32,
+}
+
+/// Arguments for the `contracts` command.
+#[derive(Args, Debug)]
+pub struct ContractsArgs {
+    #[command(flatten)]
+    pub common: ChainArgs,
+
+    /// Chain ID
+    pub chain_id: Uuid,
+}
+
+/// Arguments for the `graph` command (ASCII DAG visualization).
+#[derive(Args, Debug)]
+pub struct GraphArgs {
+    #[command(flatten)]
+    pub common: ChainArgs,
+
+    /// Chain ID
+    pub chain_id: Uuid,
+
+    /// Show contract status in nodes
+    #[arg(long)]
+    pub with_status: bool,
+}
+
+/// Arguments for the `validate` command.
+#[derive(Args, Debug)]
+pub struct ValidateArgs {
+    /// Path to the chain YAML file
+    pub file: PathBuf,
+}
+
+/// Arguments for the `preview` command.
+#[derive(Args, Debug)]
+pub struct PreviewArgs {
+    /// Path to the chain YAML file
+    pub file: PathBuf,
+}
+
+/// Arguments for the `archive` command.
+#[derive(Args, Debug)]
+pub struct ArchiveArgs {
+    #[command(flatten)]
+    pub common: ChainArgs,
+
+    /// Chain ID
+    pub chain_id: Uuid,
+}
diff --git a/makima/src/daemon/cli/mod.rs b/makima/src/daemon/cli/mod.rs
index 0805edd..035a784 100644
--- a/makima/src/daemon/cli/mod.rs
+++ b/makima/src/daemon/cli/mod.rs
@@ -1,5 +1,6 @@
 //! Command-line interface for the makima CLI.
 
+pub mod chain;
 pub mod config;
 pub mod contract;
 pub mod daemon;
@@ -9,6 +10,7 @@ pub mod view;
 
 use clap::{Parser, Subcommand};
 
+pub use chain::ChainArgs;
 pub use config::CliConfig;
 pub use contract::ContractArgs;
 pub use daemon::DaemonArgs;
@@ -58,6 +60,14 @@ pub enum Commands {
     /// Saves configuration to ~/.makima/config.toml for use by CLI commands.
     #[command(subcommand)]
     Config(ConfigCommand),
+
+    /// Chain commands for multi-contract orchestration
+    ///
+    /// Chains are DAGs (directed acyclic graphs) of contracts that work together
+    /// to achieve a larger goal. Contracts can depend on each other, and run
+    /// in parallel when no dependencies exist.
+    #[command(subcommand)]
+    Chain(ChainCommand),
 }
 
 /// Config subcommands for CLI configuration.
@@ -196,6 +206,48 @@ pub enum ContractCommand {
     CreateFile(contract::CreateFileArgs),
 }
 
+/// Chain subcommands for multi-contract orchestration.
+#[derive(Subcommand, Debug)]
+pub enum ChainCommand {
+    /// Create a chain from a YAML file
+    ///
+    /// Parses the chain definition, validates the DAG, and creates
+    /// contracts in the correct dependency order.
+    Run(chain::RunArgs),
+
+    /// Get chain status and progress
+    Status(chain::StatusArgs),
+
+    /// List all chains
+    List(chain::ListArgs),
+
+    /// List contracts in a chain
+    Contracts(chain::ContractsArgs),
+
+    /// Display ASCII DAG visualization
+    ///
+    /// Shows the chain structure as an ASCII graph with
+    /// contracts as nodes and dependencies as edges.
+    Graph(chain::GraphArgs),
+
+    /// Validate a chain YAML file without creating
+    ///
+    /// Checks syntax, validates the DAG (no cycles), and
+    /// reports any errors.
+    Validate(chain::ValidateArgs),
+
+    /// Preview what would be created from a chain file
+    ///
+    /// Shows execution order and contract details without
+    /// actually creating anything.
+    Preview(chain::PreviewArgs),
+
+    /// Archive a chain
+    ///
+    /// Marks the chain as archived. Does not delete contracts.
+    Archive(chain::ArchiveArgs),
+}
+
 impl Cli {
     /// Parse command-line arguments
     pub fn parse_args() -> Self {
diff --git a/makima/src/daemon/mod.rs b/makima/src/daemon/mod.rs
index f5793d6..62da20e 100644
--- a/makima/src/daemon/mod.rs
+++ b/makima/src/daemon/mod.rs
@@ -8,6 +8,7 @@
 //! - `makima view` - Interactive TUI browser for tasks, contracts, and files
 
 pub mod api;
+pub mod chain;
 pub mod cli;
 pub mod config;
 pub mod db;
diff --git a/makima/src/db/models.rs b/makima/src/db/models.rs
index cef0a22..45ddb52 100644
--- a/makima/src/db/models.rs
+++ b/makima/src/db/models.rs
@@ -1446,6 +1446,9 @@ pub struct Contract {
     /// Use `get_phase_config()` to get the parsed PhaseConfig.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub phase_config: Option<serde_json::Value>,
+    /// Chain ID if this contract is part of a chain (DAG of contracts)
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub chain_id: Option<Uuid>,
     pub version: i32,
     pub created_at: DateTime<Utc>,
     pub updated_at: DateTime<Utc>,
@@ -2586,6 +2589,359 @@ pub struct HeartbeatHistoryQuery {
 }
 
 // =============================================================================
+// Chains (DAG of contracts for multi-contract orchestration)
+// =============================================================================
+
+/// Chain status determines the overall state of the chain
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "lowercase")]
+pub enum ChainStatus {
+    /// Chain is actively running
+    Active,
+    /// All contracts completed successfully
+    Completed,
+    /// Chain was manually archived
+    Archived,
+}
+
+impl Default for ChainStatus {
+    fn default() -> Self {
+        ChainStatus::Active
+    }
+}
+
+impl std::fmt::Display for ChainStatus {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            ChainStatus::Active => write!(f, "active"),
+            ChainStatus::Completed => write!(f, "completed"),
+            ChainStatus::Archived => write!(f, "archived"),
+        }
+    }
+}
+
+impl std::str::FromStr for ChainStatus {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s.to_lowercase().as_str() {
+            "active" => Ok(ChainStatus::Active),
+            "completed" => Ok(ChainStatus::Completed),
+            "archived" => Ok(ChainStatus::Archived),
+            _ => Err(format!("Invalid chain status: {}", s)),
+        }
+    }
+}
+
+/// Chain - a directed acyclic graph (DAG) of contracts
+/// Fits Makima's control theme - she controls through invisible chains
+#[derive(Debug, Clone, FromRow, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct Chain {
+    pub id: Uuid,
+    pub owner_id: Uuid,
+    pub name: String,
+    pub description: Option<String>,
+    pub status: String,
+    /// Whether loop mode is enabled for iterative execution
+    #[serde(default)]
+    pub loop_enabled: bool,
+    /// Maximum loop iterations (default: 10)
+    pub loop_max_iterations: Option<i32>,
+    /// Current loop iteration count
+    pub loop_current_iteration: Option<i32>,
+    /// Progress check prompt/criteria for evaluating loop completion
+    pub loop_progress_check: Option<String>,
+    /// Repository URL for contracts in this chain (optional)
+    pub repository_url: Option<String>,
+    /// Local path for contracts in this chain (optional)
+    pub local_path: Option<String>,
+    /// Version for optimistic locking
+    pub version: i32,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: DateTime<Utc>,
+}
+
+impl Chain {
+    /// Parse status string to ChainStatus enum
+    pub fn status_enum(&self) -> Result<ChainStatus, String> {
+        self.status.parse()
+    }
+}
+
+/// Chain contract link - links contracts to chains with DAG dependency info
+#[derive(Debug, Clone, FromRow, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainContract {
+    pub id: Uuid,
+    pub chain_id: Uuid,
+    pub contract_id: Uuid,
+    /// Contract IDs this contract depends on (DAG edges)
+    #[sqlx(default)]
+    pub depends_on: Vec<Uuid>,
+    /// Order for display/processing (topological sort order)
+    pub order_index: i32,
+    /// X position for GUI editor
+    pub editor_x: Option<f64>,
+    /// Y position for GUI editor
+    pub editor_y: Option<f64>,
+    pub created_at: DateTime<Utc>,
+}
+
+/// Chain event for audit trail
+#[derive(Debug, Clone, FromRow, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainEvent {
+    pub id: Uuid,
+    pub chain_id: Uuid,
+    pub event_type: String,
+    pub contract_id: Option<Uuid>,
+    #[sqlx(json)]
+    pub event_data: Option<serde_json::Value>,
+    pub created_at: DateTime<Utc>,
+}
+
+/// Summary of a chain for list views
+#[derive(Debug, Clone, FromRow, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainSummary {
+    pub id: Uuid,
+    pub name: String,
+    pub description: Option<String>,
+    pub status: String,
+    pub loop_enabled: bool,
+    pub loop_current_iteration: Option<i32>,
+    pub contract_count: i64,
+    pub completed_count: i64,
+    pub version: i32,
+    pub created_at: DateTime<Utc>,
+}
+
+/// Chain with contracts for detail view
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainWithContracts {
+    #[serde(flatten)]
+    pub chain: Chain,
+    pub contracts: Vec<ChainContractDetail>,
+}
+
+/// Contract detail within a chain (includes contract info + chain link info)
+#[derive(Debug, Clone, FromRow, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainContractDetail {
+    pub chain_contract_id: Uuid,
+    pub contract_id: Uuid,
+    pub contract_name: String,
+    pub contract_status: String,
+    pub contract_phase: String,
+    #[sqlx(default)]
+    pub depends_on: Vec<Uuid>,
+    pub order_index: i32,
+    pub editor_x: Option<f64>,
+    pub editor_y: Option<f64>,
+}
+
+/// DAG graph structure for visualization
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainGraphResponse {
+    pub chain_id: Uuid,
+    pub chain_name: String,
+    pub chain_status: String,
+    pub nodes: Vec<ChainGraphNode>,
+    pub edges: Vec<ChainGraphEdge>,
+}
+
+/// Node in chain DAG graph
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainGraphNode {
+    pub id: Uuid,
+    pub contract_id: Uuid,
+    pub name: String,
+    pub status: String,
+    pub phase: String,
+    pub x: f64,
+    pub y: f64,
+}
+
+/// Edge in chain DAG graph
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainGraphEdge {
+    pub from: Uuid,
+    pub to: Uuid,
+}
+
+/// Response for chain list endpoint
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainListResponse {
+    pub chains: Vec<ChainSummary>,
+    pub total: i64,
+}
+
+/// Request payload for creating a new chain
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct CreateChainRequest {
+    /// Name of the chain
+    pub name: String,
+    /// Optional description
+    pub description: Option<String>,
+    /// Repository URL for contracts in this chain
+    pub repository_url: Option<String>,
+    /// Local path for contracts in this chain
+    pub local_path: Option<String>,
+    /// Enable loop mode for iterative execution
+    #[serde(default)]
+    pub loop_enabled: Option<bool>,
+    /// Maximum loop iterations (default: 10)
+    pub loop_max_iterations: Option<i32>,
+    /// Progress check prompt for evaluating loop completion
+    pub loop_progress_check: Option<String>,
+    /// Contracts to create within this chain
+    pub contracts: Option<Vec<CreateChainContractRequest>>,
+}
+
+/// Request to create a contract within a chain
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct CreateChainContractRequest {
+    /// Name of the contract
+    pub name: String,
+    /// Optional description
+    pub description: Option<String>,
+    /// Contract type
+    #[serde(default)]
+    pub contract_type: Option<String>,
+    /// Initial phase
+    pub initial_phase: Option<String>,
+    /// Phases for the contract
+    pub phases: Option<Vec<String>>,
+    /// Names of contracts this depends on (resolved to IDs)
+    pub depends_on: Option<Vec<String>>,
+    /// Tasks to create in this contract
+    pub tasks: Option<Vec<CreateChainTaskRequest>>,
+    /// Deliverables for this contract
+    pub deliverables: Option<Vec<CreateChainDeliverableRequest>>,
+    /// Position in GUI editor
+    pub editor_x: Option<f64>,
+    pub editor_y: Option<f64>,
+}
+
+/// Task definition within a chain contract
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct CreateChainTaskRequest {
+    pub name: String,
+    pub plan: String,
+}
+
+/// Deliverable definition within a chain contract
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct CreateChainDeliverableRequest {
+    pub id: String,
+    pub name: String,
+    pub priority: Option<String>,
+}
+
+/// Request to update an existing chain
+#[derive(Debug, Clone, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct UpdateChainRequest {
+    pub name: Option<String>,
+    pub description: Option<String>,
+    pub status: Option<String>,
+    pub loop_enabled: Option<bool>,
+    pub loop_max_iterations: Option<i32>,
+    pub loop_progress_check: Option<String>,
+    /// Version for optimistic locking
+    pub version: Option<i32>,
+}
+
+/// Request to add a contract to a chain
+#[derive(Debug, Clone, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct AddContractToChainRequest {
+    /// Existing contract ID to add
+    pub contract_id: Option<Uuid>,
+    /// Or create a new contract with this definition
+    pub new_contract: Option<CreateChainContractRequest>,
+    /// Contract IDs this depends on
+    pub depends_on: Option<Vec<Uuid>>,
+    /// Position in GUI editor
+    pub editor_x: Option<f64>,
+    pub editor_y: Option<f64>,
+}
+
+/// Editor data model for GUI chain editor
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainEditorData {
+    pub id: Option<Uuid>,
+    pub name: String,
+    pub description: Option<String>,
+    pub repository_url: Option<String>,
+    pub local_path: Option<String>,
+    pub loop_enabled: bool,
+    pub loop_max_iterations: Option<i32>,
+    pub loop_progress_check: Option<String>,
+    pub nodes: Vec<ChainEditorNode>,
+    pub edges: Vec<ChainEditorEdge>,
+}
+
+/// Node in chain editor
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainEditorNode {
+    pub id: String,
+    pub x: f64,
+    pub y: f64,
+    pub contract: ChainEditorContract,
+}
+
+/// Contract data in chain editor node
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainEditorContract {
+    pub name: String,
+    pub description: Option<String>,
+    #[serde(rename = "type")]
+    pub contract_type: String,
+    pub phases: Vec<String>,
+    pub tasks: Vec<ChainEditorTask>,
+    pub deliverables: Vec<ChainEditorDeliverable>,
+}
+
+/// Task in chain editor
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainEditorTask {
+    pub name: String,
+    pub plan: String,
+}
+
+/// Deliverable in chain editor
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainEditorDeliverable {
+    pub id: String,
+    pub name: String,
+    pub priority: String,
+}
+
+/// Edge in chain editor
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainEditorEdge {
+    pub from: String,
+    pub to: String,
+}
+
+// =============================================================================
 // Unit Tests
 // =============================================================================
 
diff --git a/makima/src/db/repository.rs b/makima/src/db/repository.rs
index 2ecbc4a..48b0714 100644
--- a/makima/src/db/repository.rs
+++ b/makima/src/db/repository.rs
@@ -6,15 +6,19 @@ use sqlx::PgPool;
 use uuid::Uuid;
 
 use super::models::{
-    CheckpointPatch, CheckpointPatchInfo, Contract, ContractChatConversation,
-    ContractChatMessageRecord, ContractEvent, ContractRepository, ContractSummary,
-    ContractTypeTemplateRecord, ConversationMessage, ConversationSnapshot, CreateContractRequest,
-    CreateFileRequest, CreateTaskRequest, CreateTemplateRequest, Daemon, DaemonTaskAssignment,
-    DaemonWithCapacity, DeliverableDefinition, File, FileSummary, FileVersion, HistoryEvent,
-    HistoryQueryFilters, MeshChatConversation, MeshChatMessageRecord, PhaseChangeResult,
-    PhaseConfig, PhaseDefinition, SupervisorHeartbeatRecord, SupervisorState,
-    Task, TaskCheckpoint, TaskEvent, TaskSummary, UpdateContractRequest, UpdateFileRequest,
-    UpdateTaskRequest, UpdateTemplateRequest,
+    AddContractToChainRequest, Chain, ChainContract, ChainContractDetail, ChainEditorContract,
+    ChainEditorData, ChainEditorDeliverable, ChainEditorEdge, ChainEditorNode, ChainEditorTask,
+    ChainEvent, ChainGraphEdge, ChainGraphNode, ChainGraphResponse, ChainSummary,
+    ChainWithContracts, CheckpointPatch, CheckpointPatchInfo, Contract,
+    ContractChatConversation, ContractChatMessageRecord, ContractEvent, ContractRepository,
+    ContractSummary, ContractTypeTemplateRecord, ConversationMessage, ConversationSnapshot,
+    CreateChainRequest, CreateContractRequest, CreateFileRequest, CreateTaskRequest,
+    CreateTemplateRequest, Daemon, DaemonTaskAssignment, DaemonWithCapacity,
+    DeliverableDefinition, File, FileSummary, FileVersion, HistoryEvent, HistoryQueryFilters,
+    MeshChatConversation, MeshChatMessageRecord, PhaseChangeResult, PhaseConfig, PhaseDefinition,
+    SupervisorHeartbeatRecord, SupervisorState, Task, TaskCheckpoint, TaskEvent, TaskSummary,
+    UpdateChainRequest, UpdateContractRequest, UpdateFileRequest, UpdateTaskRequest,
+    UpdateTemplateRequest,
 };
 
 /// Repository error types.
@@ -4896,3 +4900,529 @@ pub async fn sync_supervisor_state(
     .fetch_optional(pool)
     .await
 }
+
+// =============================================================================
+// Chain Operations (DAG of contracts for multi-contract orchestration)
+// =============================================================================
+
+/// Create a new chain for a specific owner.
+pub async fn create_chain_for_owner(
+    pool: &PgPool,
+    owner_id: Uuid,
+    req: CreateChainRequest,
+) -> Result<Chain, sqlx::Error> {
+    let loop_enabled = req.loop_enabled.unwrap_or(false);
+    let loop_max_iterations = req.loop_max_iterations.unwrap_or(10);
+
+    sqlx::query_as::<_, Chain>(
+        r#"
+        INSERT INTO chains (owner_id, name, description, repository_url, local_path, loop_enabled, loop_max_iterations, loop_progress_check)
+        VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+        RETURNING *
+        "#,
+    )
+    .bind(owner_id)
+    .bind(&req.name)
+    .bind(&req.description)
+    .bind(&req.repository_url)
+    .bind(&req.local_path)
+    .bind(loop_enabled)
+    .bind(loop_max_iterations)
+    .bind(&req.loop_progress_check)
+    .fetch_one(pool)
+    .await
+}
+
+/// Get a chain by ID, scoped to owner.
+pub async fn get_chain_for_owner(
+    pool: &PgPool,
+    id: Uuid,
+    owner_id: Uuid,
+) -> Result<Option<Chain>, sqlx::Error> {
+    sqlx::query_as::<_, Chain>(
+        r#"
+        SELECT *
+        FROM chains
+        WHERE id = $1 AND owner_id = $2
+        "#,
+    )
+    .bind(id)
+    .bind(owner_id)
+    .fetch_optional(pool)
+    .await
+}
+
+/// Get a chain by ID (no owner check - for internal use).
+pub async fn get_chain(pool: &PgPool, id: Uuid) -> Result<Option<Chain>, sqlx::Error> {
+    sqlx::query_as::<_, Chain>(
+        r#"
+        SELECT *
+        FROM chains
+        WHERE id = $1
+        "#,
+    )
+    .bind(id)
+    .fetch_optional(pool)
+    .await
+}
+
+/// List chains for a specific owner.
+pub async fn list_chains_for_owner(
+    pool: &PgPool,
+    owner_id: Uuid,
+) -> Result<Vec<ChainSummary>, sqlx::Error> {
+    sqlx::query_as::<_, ChainSummary>(
+        r#"
+        SELECT
+            c.id,
+            c.name,
+            c.description,
+            c.status,
+            c.loop_enabled,
+            c.loop_current_iteration,
+            COUNT(DISTINCT cc.contract_id) as contract_count,
+            COUNT(DISTINCT CASE WHEN con.status = 'completed' THEN cc.contract_id END) as completed_count,
+            c.version,
+            c.created_at
+        FROM chains c
+        LEFT JOIN chain_contracts cc ON cc.chain_id = c.id
+        LEFT JOIN contracts con ON con.id = cc.contract_id
+        WHERE c.owner_id = $1
+        GROUP BY c.id
+        ORDER BY c.created_at DESC
+        "#,
+    )
+    .bind(owner_id)
+    .fetch_all(pool)
+    .await
+}
+
+/// Update a chain.
+pub async fn update_chain_for_owner(
+    pool: &PgPool,
+    id: Uuid,
+    owner_id: Uuid,
+    req: UpdateChainRequest,
+) -> Result<Chain, RepositoryError> {
+    // First get current version if optimistic locking requested
+    if let Some(expected_version) = req.version {
+        let current: Option<(i32,)> = sqlx::query_as(
+            "SELECT version FROM chains WHERE id = $1 AND owner_id = $2",
+        )
+        .bind(id)
+        .bind(owner_id)
+        .fetch_optional(pool)
+        .await?;
+
+        if let Some((actual_version,)) = current {
+            if actual_version != expected_version {
+                return Err(RepositoryError::VersionConflict {
+                    expected: expected_version,
+                    actual: actual_version,
+                });
+            }
+        }
+    }
+
+    let result = sqlx::query_as::<_, Chain>(
+        r#"
+        UPDATE chains
+        SET
+            name = COALESCE($3, name),
+            description = COALESCE($4, description),
+            status = COALESCE($5, status),
+            loop_enabled = COALESCE($6, loop_enabled),
+            loop_max_iterations = COALESCE($7, loop_max_iterations),
+            loop_progress_check = COALESCE($8, loop_progress_check),
+            version = version + 1,
+            updated_at = NOW()
+        WHERE id = $1 AND owner_id = $2
+        RETURNING *
+        "#,
+    )
+    .bind(id)
+    .bind(owner_id)
+    .bind(&req.name)
+    .bind(&req.description)
+    .bind(&req.status)
+    .bind(req.loop_enabled)
+    .bind(req.loop_max_iterations)
+    .bind(&req.loop_progress_check)
+    .fetch_one(pool)
+    .await?;
+
+    Ok(result)
+}
+
+/// Delete (archive) a chain.
+pub async fn delete_chain_for_owner(
+    pool: &PgPool,
+    id: Uuid,
+    owner_id: Uuid,
+) -> Result<bool, sqlx::Error> {
+    let result = sqlx::query(
+        r#"
+        UPDATE chains
+        SET status = 'archived', updated_at = NOW()
+        WHERE id = $1 AND owner_id = $2
+        "#,
+    )
+    .bind(id)
+    .bind(owner_id)
+    .execute(pool)
+    .await?;
+
+    Ok(result.rows_affected() > 0)
+}
+
+/// Add a contract to a chain.
+pub async fn add_contract_to_chain(
+    pool: &PgPool,
+    chain_id: Uuid,
+    contract_id: Uuid,
+    depends_on: Vec<Uuid>,
+    order_index: i32,
+    editor_x: Option<f64>,
+    editor_y: Option<f64>,
+) -> Result<ChainContract, sqlx::Error> {
+    // Also update the contract's chain_id
+    sqlx::query("UPDATE contracts SET chain_id = $1 WHERE id = $2")
+        .bind(chain_id)
+        .bind(contract_id)
+        .execute(pool)
+        .await?;
+
+    sqlx::query_as::<_, ChainContract>(
+        r#"
+        INSERT INTO chain_contracts (chain_id, contract_id, depends_on, order_index, editor_x, editor_y)
+        VALUES ($1, $2, $3, $4, $5, $6)
+        ON CONFLICT (chain_id, contract_id) DO UPDATE SET
+            depends_on = EXCLUDED.depends_on,
+            order_index = EXCLUDED.order_index,
+            editor_x = EXCLUDED.editor_x,
+            editor_y = EXCLUDED.editor_y
+        RETURNING *
+        "#,
+    )
+    .bind(chain_id)
+    .bind(contract_id)
+    .bind(&depends_on)
+    .bind(order_index)
+    .bind(editor_x)
+    .bind(editor_y)
+    .fetch_one(pool)
+    .await
+}
+
+/// Remove a contract from a chain.
+pub async fn remove_contract_from_chain(
+    pool: &PgPool,
+    chain_id: Uuid,
+    contract_id: Uuid,
+) -> Result<bool, sqlx::Error> {
+    // Clear the contract's chain_id
+    sqlx::query("UPDATE contracts SET chain_id = NULL WHERE id = $1 AND chain_id = $2")
+        .bind(contract_id)
+        .bind(chain_id)
+        .execute(pool)
+        .await?;
+
+    let result = sqlx::query(
+        r#"
+        DELETE FROM chain_contracts
+        WHERE chain_id = $1 AND contract_id = $2
+        "#,
+    )
+    .bind(chain_id)
+    .bind(contract_id)
+    .execute(pool)
+    .await?;
+
+    Ok(result.rows_affected() > 0)
+}
+
+/// List contracts in a chain with their details.
+pub async fn list_chain_contracts(
+    pool: &PgPool,
+    chain_id: Uuid,
+) -> Result<Vec<ChainContractDetail>, sqlx::Error> {
+    sqlx::query_as::<_, ChainContractDetail>(
+        r#"
+        SELECT
+            cc.id as chain_contract_id,
+            cc.contract_id,
+            c.name as contract_name,
+            c.status as contract_status,
+            c.phase as contract_phase,
+            cc.depends_on,
+            cc.order_index,
+            cc.editor_x,
+            cc.editor_y
+        FROM chain_contracts cc
+        JOIN contracts c ON c.id = cc.contract_id
+        WHERE cc.chain_id = $1
+        ORDER BY cc.order_index ASC
+        "#,
+    )
+    .bind(chain_id)
+    .fetch_all(pool)
+    .await
+}
+
+/// Get chain with all contracts for detail view.
+pub async fn get_chain_with_contracts(
+    pool: &PgPool,
+    chain_id: Uuid,
+    owner_id: Uuid,
+) -> Result<Option<ChainWithContracts>, sqlx::Error> {
+    let chain = get_chain_for_owner(pool, chain_id, owner_id).await?;
+
+    match chain {
+        Some(chain) => {
+            let contracts = list_chain_contracts(pool, chain_id).await?;
+            Ok(Some(ChainWithContracts { chain, contracts }))
+        }
+        None => Ok(None),
+    }
+}
+
+/// Get chain graph structure for visualization.
+pub async fn get_chain_graph(
+    pool: &PgPool,
+    chain_id: Uuid,
+) -> Result<Option<ChainGraphResponse>, sqlx::Error> {
+    let chain = get_chain(pool, chain_id).await?;
+
+    match chain {
+        Some(chain) => {
+            let contracts = list_chain_contracts(pool, chain_id).await?;
+
+            let nodes: Vec<ChainGraphNode> = contracts
+                .iter()
+                .map(|c| ChainGraphNode {
+                    id: c.chain_contract_id,
+                    contract_id: c.contract_id,
+                    name: c.contract_name.clone(),
+                    status: c.contract_status.clone(),
+                    phase: c.contract_phase.clone(),
+                    x: c.editor_x.unwrap_or(0.0),
+                    y: c.editor_y.unwrap_or(0.0),
+                })
+                .collect();
+
+            let mut edges: Vec<ChainGraphEdge> = Vec::new();
+            for contract in &contracts {
+                for dep_id in &contract.depends_on {
+                    // Find the chain_contract_id for this dependency
+                    if let Some(dep) = contracts.iter().find(|c| c.contract_id == *dep_id) {
+                        edges.push(ChainGraphEdge {
+                            from: dep.chain_contract_id,
+                            to: contract.chain_contract_id,
+                        });
+                    }
+                }
+            }
+
+            Ok(Some(ChainGraphResponse {
+                chain_id: chain.id,
+                chain_name: chain.name,
+                chain_status: chain.status,
+                nodes,
+                edges,
+            }))
+        }
+        None => Ok(None),
+    }
+}
+
+/// Record a chain event.
+pub async fn record_chain_event(
+    pool: &PgPool,
+    chain_id: Uuid,
+    event_type: &str,
+    contract_id: Option<Uuid>,
+    event_data: Option<serde_json::Value>,
+) -> Result<ChainEvent, sqlx::Error> {
+    sqlx::query_as::<_, ChainEvent>(
+        r#"
+        INSERT INTO chain_events (chain_id, event_type, contract_id, event_data)
+        VALUES ($1, $2, $3, $4)
+        RETURNING *
+        "#,
+    )
+    .bind(chain_id)
+    .bind(event_type)
+    .bind(contract_id)
+    .bind(event_data)
+    .fetch_one(pool)
+    .await
+}
+
+/// List chain events.
+pub async fn list_chain_events(
+    pool: &PgPool,
+    chain_id: Uuid,
+) -> Result<Vec<ChainEvent>, sqlx::Error> {
+    sqlx::query_as::<_, ChainEvent>(
+        r#"
+        SELECT *
+        FROM chain_events
+        WHERE chain_id = $1
+        ORDER BY created_at DESC
+        "#,
+    )
+    .bind(chain_id)
+    .fetch_all(pool)
+    .await
+}
+
+/// Increment chain loop iteration.
+pub async fn increment_chain_loop(pool: &PgPool, chain_id: Uuid) -> Result<Chain, sqlx::Error> {
+    sqlx::query_as::<_, Chain>(
+        r#"
+        UPDATE chains
+        SET loop_current_iteration = COALESCE(loop_current_iteration, 0) + 1,
+            updated_at = NOW()
+        WHERE id = $1
+        RETURNING *
+        "#,
+    )
+    .bind(chain_id)
+    .fetch_one(pool)
+    .await
+}
+
+/// Mark a chain as completed.
+pub async fn complete_chain(pool: &PgPool, chain_id: Uuid) -> Result<Chain, sqlx::Error> {
+    sqlx::query_as::<_, Chain>(
+        r#"
+        UPDATE chains
+        SET status = 'completed',
+            updated_at = NOW()
+        WHERE id = $1
+        RETURNING *
+        "#,
+    )
+    .bind(chain_id)
+    .fetch_one(pool)
+    .await
+}
+
+/// Get contracts in a chain that have no pending dependencies (ready to start).
+/// Returns contracts where all depends_on contracts are completed.
+pub async fn get_ready_chain_contracts(
+    pool: &PgPool,
+    chain_id: Uuid,
+) -> Result<Vec<ChainContractDetail>, sqlx::Error> {
+    sqlx::query_as::<_, ChainContractDetail>(
+        r#"
+        SELECT
+            cc.id as chain_contract_id,
+            cc.contract_id,
+            c.name as contract_name,
+            c.status as contract_status,
+            c.phase as contract_phase,
+            cc.depends_on,
+            cc.order_index,
+            cc.editor_x,
+            cc.editor_y
+        FROM chain_contracts cc
+        JOIN contracts c ON c.id = cc.contract_id
+        WHERE cc.chain_id = $1
+          AND c.status = 'active'
+          AND (
+            -- No dependencies
+            cc.depends_on IS NULL
+            OR array_length(cc.depends_on, 1) IS NULL
+            OR array_length(cc.depends_on, 1) = 0
+            -- Or all dependencies completed
+            OR NOT EXISTS (
+                SELECT 1
+                FROM unnest(cc.depends_on) AS dep_id
+                JOIN contracts dep ON dep.id = dep_id
+                WHERE dep.status != 'completed'
+            )
+          )
+        ORDER BY cc.order_index ASC
+        "#,
+    )
+    .bind(chain_id)
+    .fetch_all(pool)
+    .await
+}
+
+/// Check if all contracts in a chain are completed.
+pub async fn is_chain_complete(pool: &PgPool, chain_id: Uuid) -> Result<bool, sqlx::Error> {
+    let result: (i64,) = sqlx::query_as(
+        r#"
+        SELECT COUNT(*)
+        FROM chain_contracts cc
+        JOIN contracts c ON c.id = cc.contract_id
+        WHERE cc.chain_id = $1
+          AND c.status != 'completed'
+        "#,
+    )
+    .bind(chain_id)
+    .fetch_one(pool)
+    .await?;
+
+    Ok(result.0 == 0)
+}
+
+/// Get chain editor data for the GUI editor.
+pub async fn get_chain_editor_data(
+    pool: &PgPool,
+    chain_id: Uuid,
+    owner_id: Uuid,
+) -> Result<Option<ChainEditorData>, sqlx::Error> {
+    let chain = get_chain_for_owner(pool, chain_id, owner_id).await?;
+
+    match chain {
+        Some(chain) => {
+            let contracts = list_chain_contracts(pool, chain_id).await?;
+
+            // Build nodes
+            let nodes: Vec<ChainEditorNode> = contracts
+                .iter()
+                .map(|c| ChainEditorNode {
+                    id: c.contract_id.to_string(),
+                    x: c.editor_x.unwrap_or(0.0),
+                    y: c.editor_y.unwrap_or(0.0),
+                    contract: ChainEditorContract {
+                        name: c.contract_name.clone(),
+                        description: None, // Would need to join with full contract data
+                        contract_type: "simple".to_string(),
+                        phases: vec!["plan".to_string(), "execute".to_string()],
+                        tasks: vec![],
+                        deliverables: vec![],
+                    },
+                })
+                .collect();
+
+            // Build edges
+            let edges: Vec<ChainEditorEdge> = contracts
+                .iter()
+                .flat_map(|c| {
+                    c.depends_on.iter().map(move |dep_id| ChainEditorEdge {
+                        from: dep_id.to_string(),
+                        to: c.contract_id.to_string(),
+                    })
+                })
+                .collect();
+
+            Ok(Some(ChainEditorData {
+                id: Some(chain.id),
+                name: chain.name,
+                description: chain.description,
+                repository_url: chain.repository_url,
+                local_path: chain.local_path,
+                loop_enabled: chain.loop_enabled,
+                loop_max_iterations: chain.loop_max_iterations,
+                loop_progress_check: chain.loop_progress_check,
+                nodes,
+                edges,
+            }))
+        }
+        None => Ok(None),
+    }
+}
diff --git a/makima/src/server/handlers/chains.rs b/makima/src/server/handlers/chains.rs
new file mode 100644
index 0000000..136a868
--- /dev/null
+++ b/makima/src/server/handlers/chains.rs
@@ -0,0 +1,609 @@
+//! HTTP handlers for chain CRUD operations.
+//!
+//! Chains are DAGs (directed acyclic graphs) of contracts for multi-contract orchestration.
+
+use axum::{
+    extract::{Path, Query, State},
+    http::StatusCode,
+    response::IntoResponse,
+    Json,
+};
+use serde::Deserialize;
+use utoipa::ToSchema;
+use uuid::Uuid;
+
+use crate::db::models::{
+    ChainContractDetail, ChainEditorData, ChainEvent, ChainGraphResponse, ChainSummary,
+    ChainWithContracts, CreateChainRequest, UpdateChainRequest,
+};
+use crate::db::repository::{self, RepositoryError};
+use crate::server::auth::Authenticated;
+use crate::server::messages::ApiError;
+use crate::server::state::SharedState;
+
+// =============================================================================
+// Query Parameters
+// =============================================================================
+
+/// Query parameters for listing chains.
+#[derive(Debug, Deserialize, ToSchema)]
+pub struct ListChainsQuery {
+    /// Filter by status (active, completed, archived)
+    pub status: Option<String>,
+    /// Maximum number of results
+    #[serde(default = "default_limit")]
+    pub limit: i32,
+    /// Offset for pagination
+    #[serde(default)]
+    pub offset: i32,
+}
+
+fn default_limit() -> i32 {
+    50
+}
+
+// =============================================================================
+// Response Types
+// =============================================================================
+
+/// Response for listing chains.
+#[derive(Debug, serde::Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ChainListResponse {
+    pub chains: Vec<ChainSummary>,
+    pub total: i64,
+}
+
+// =============================================================================
+// Handlers
+// =============================================================================
+
+/// List chains for the authenticated user.
+///
+/// GET /api/v1/chains
+#[utoipa::path(
+    get,
+    path = "/api/v1/chains",
+    responses(
+        (status = 200, description = "List of chains", body = ChainListResponse),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn list_chains(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Query(query): Query<ListChainsQuery>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    match repository::list_chains_for_owner(pool, auth.owner_id).await {
+        Ok(mut chains) => {
+            // Apply filters
+            if let Some(status) = &query.status {
+                chains.retain(|c| c.status == *status);
+            }
+            // Apply pagination
+            let total = chains.len() as i64;
+            let chains: Vec<_> = chains
+                .into_iter()
+                .skip(query.offset as usize)
+                .take(query.limit as usize)
+                .collect();
+            Json(ChainListResponse { chains, total }).into_response()
+        }
+        Err(e) => {
+            tracing::error!("Failed to list chains: {}", e);
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response()
+        }
+    }
+}
+
+/// Create a new chain with contracts.
+///
+/// POST /api/v1/chains
+#[utoipa::path(
+    post,
+    path = "/api/v1/chains",
+    request_body = CreateChainRequest,
+    responses(
+        (status = 201, description = "Chain created"),
+        (status = 400, description = "Invalid request", body = ApiError),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn create_chain(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Json(req): Json<CreateChainRequest>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    // Validate the request
+    if req.name.trim().is_empty() {
+        return (
+            StatusCode::BAD_REQUEST,
+            Json(ApiError::new("VALIDATION_ERROR", "Chain name cannot be empty")),
+        )
+            .into_response();
+    }
+
+    match repository::create_chain_for_owner(pool, auth.owner_id, req).await {
+        Ok(chain) => (StatusCode::CREATED, Json(chain)).into_response(),
+        Err(e) => {
+            tracing::error!("Failed to create chain: {}", e);
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response()
+        }
+    }
+}
+
+/// Get a chain by ID.
+///
+/// GET /api/v1/chains/{id}
+#[utoipa::path(
+    get,
+    path = "/api/v1/chains/{id}",
+    params(
+        ("id" = Uuid, Path, description = "Chain ID")
+    ),
+    responses(
+        (status = 200, description = "Chain with contracts", body = ChainWithContracts),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 404, description = "Chain not found", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn get_chain(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Path(chain_id): Path<Uuid>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    match repository::get_chain_with_contracts(pool, chain_id, auth.owner_id).await {
+        Ok(Some(chain)) => Json(chain).into_response(),
+        Ok(None) => (
+            StatusCode::NOT_FOUND,
+            Json(ApiError::new("NOT_FOUND", "Chain not found")),
+        )
+            .into_response(),
+        Err(e) => {
+            tracing::error!("Failed to get chain: {}", e);
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response()
+        }
+    }
+}
+
+/// Update a chain.
+///
+/// PUT /api/v1/chains/{id}
+#[utoipa::path(
+    put,
+    path = "/api/v1/chains/{id}",
+    params(
+        ("id" = Uuid, Path, description = "Chain ID")
+    ),
+    request_body = UpdateChainRequest,
+    responses(
+        (status = 200, description = "Chain updated"),
+        (status = 400, description = "Invalid request", body = ApiError),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 404, description = "Chain not found", body = ApiError),
+        (status = 409, description = "Version conflict", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn update_chain(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Path(chain_id): Path<Uuid>,
+    Json(req): Json<UpdateChainRequest>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    match repository::update_chain_for_owner(pool, chain_id, auth.owner_id, req).await {
+        Ok(chain) => Json(chain).into_response(),
+        Err(RepositoryError::VersionConflict { expected, actual }) => (
+            StatusCode::CONFLICT,
+            Json(ApiError::new(
+                "VERSION_CONFLICT",
+                format!("Version conflict: expected {}, found {}", expected, actual),
+            )),
+        )
+            .into_response(),
+        Err(RepositoryError::Database(e)) => {
+            // Check if it's a "row not found" error
+            let error_str = e.to_string();
+            if error_str.contains("no rows") || error_str.contains("RowNotFound") {
+                (
+                    StatusCode::NOT_FOUND,
+                    Json(ApiError::new("NOT_FOUND", "Chain not found")),
+                )
+                    .into_response()
+            } else {
+                tracing::error!("Failed to update chain: {}", e);
+                (
+                    StatusCode::INTERNAL_SERVER_ERROR,
+                    Json(ApiError::new("DB_ERROR", e.to_string())),
+                )
+                    .into_response()
+            }
+        }
+    }
+}
+
+/// Delete (archive) a chain.
+///
+/// DELETE /api/v1/chains/{id}
+#[utoipa::path(
+    delete,
+    path = "/api/v1/chains/{id}",
+    params(
+        ("id" = Uuid, Path, description = "Chain ID")
+    ),
+    responses(
+        (status = 200, description = "Chain archived"),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 404, description = "Chain not found", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn delete_chain(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Path(chain_id): Path<Uuid>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    match repository::delete_chain_for_owner(pool, chain_id, auth.owner_id).await {
+        Ok(true) => Json(serde_json::json!({"archived": true})).into_response(),
+        Ok(false) => (
+            StatusCode::NOT_FOUND,
+            Json(ApiError::new("NOT_FOUND", "Chain not found")),
+        )
+            .into_response(),
+        Err(e) => {
+            tracing::error!("Failed to delete chain: {}", e);
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response()
+        }
+    }
+}
+
+/// Get contracts in a chain.
+///
+/// GET /api/v1/chains/{id}/contracts
+#[utoipa::path(
+    get,
+    path = "/api/v1/chains/{id}/contracts",
+    params(
+        ("id" = Uuid, Path, description = "Chain ID")
+    ),
+    responses(
+        (status = 200, description = "List of contracts in chain", body = Vec<ChainContractDetail>),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 404, description = "Chain not found", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn get_chain_contracts(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Path(chain_id): Path<Uuid>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    // Verify ownership
+    match repository::get_chain_for_owner(pool, chain_id, auth.owner_id).await {
+        Ok(Some(_)) => {}
+        Ok(None) => {
+            return (
+                StatusCode::NOT_FOUND,
+                Json(ApiError::new("NOT_FOUND", "Chain not found")),
+            )
+                .into_response();
+        }
+        Err(e) => {
+            tracing::error!("Failed to verify chain ownership: {}", e);
+            return (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response();
+        }
+    }
+
+    match repository::list_chain_contracts(pool, chain_id).await {
+        Ok(contracts) => Json(contracts).into_response(),
+        Err(e) => {
+            tracing::error!("Failed to list chain contracts: {}", e);
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response()
+        }
+    }
+}
+
+/// Get chain DAG structure for visualization.
+///
+/// GET /api/v1/chains/{id}/graph
+#[utoipa::path(
+    get,
+    path = "/api/v1/chains/{id}/graph",
+    params(
+        ("id" = Uuid, Path, description = "Chain ID")
+    ),
+    responses(
+        (status = 200, description = "Chain graph structure", body = ChainGraphResponse),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 404, description = "Chain not found", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn get_chain_graph(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Path(chain_id): Path<Uuid>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    // Verify ownership first
+    match repository::get_chain_for_owner(pool, chain_id, auth.owner_id).await {
+        Ok(Some(_)) => {}
+        Ok(None) => {
+            return (
+                StatusCode::NOT_FOUND,
+                Json(ApiError::new("NOT_FOUND", "Chain not found")),
+            )
+                .into_response();
+        }
+        Err(e) => {
+            tracing::error!("Failed to verify chain ownership: {}", e);
+            return (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response();
+        }
+    }
+
+    match repository::get_chain_graph(pool, chain_id).await {
+        Ok(Some(graph)) => Json(graph).into_response(),
+        Ok(None) => (
+            StatusCode::NOT_FOUND,
+            Json(ApiError::new("NOT_FOUND", "Chain not found")),
+        )
+            .into_response(),
+        Err(e) => {
+            tracing::error!("Failed to get chain graph: {}", e);
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response()
+        }
+    }
+}
+
+/// Get chain events.
+///
+/// GET /api/v1/chains/{id}/events
+#[utoipa::path(
+    get,
+    path = "/api/v1/chains/{id}/events",
+    params(
+        ("id" = Uuid, Path, description = "Chain ID")
+    ),
+    responses(
+        (status = 200, description = "Chain events", body = Vec<ChainEvent>),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 404, description = "Chain not found", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn get_chain_events(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Path(chain_id): Path<Uuid>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    // Verify ownership
+    match repository::get_chain_for_owner(pool, chain_id, auth.owner_id).await {
+        Ok(Some(_)) => {}
+        Ok(None) => {
+            return (
+                StatusCode::NOT_FOUND,
+                Json(ApiError::new("NOT_FOUND", "Chain not found")),
+            )
+                .into_response();
+        }
+        Err(e) => {
+            tracing::error!("Failed to verify chain ownership: {}", e);
+            return (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response();
+        }
+    }
+
+    match repository::list_chain_events(pool, chain_id).await {
+        Ok(events) => Json(events).into_response(),
+        Err(e) => {
+            tracing::error!("Failed to list chain events: {}", e);
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response()
+        }
+    }
+}
+
+/// Get chain editor data.
+///
+/// GET /api/v1/chains/{id}/editor
+#[utoipa::path(
+    get,
+    path = "/api/v1/chains/{id}/editor",
+    params(
+        ("id" = Uuid, Path, description = "Chain ID")
+    ),
+    responses(
+        (status = 200, description = "Chain editor data", body = ChainEditorData),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 404, description = "Chain not found", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError)
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Chains"
+)]
+pub async fn get_chain_editor(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Path(chain_id): Path<Uuid>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    match repository::get_chain_editor_data(pool, chain_id, auth.owner_id).await {
+        Ok(Some(editor_data)) => Json(editor_data).into_response(),
+        Ok(None) => (
+            StatusCode::NOT_FOUND,
+            Json(ApiError::new("NOT_FOUND", "Chain not found")),
+        )
+            .into_response(),
+        Err(e) => {
+            tracing::error!("Failed to get chain editor data: {}", e);
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response()
+        }
+    }
+}
diff --git a/makima/src/server/handlers/mod.rs b/makima/src/server/handlers/mod.rs
index ae370c9..5e172bc 100644
--- a/makima/src/server/handlers/mod.rs
+++ b/makima/src/server/handlers/mod.rs
@@ -1,6 +1,7 @@
 //! HTTP and WebSocket request handlers.
 
 pub mod api_keys;
+pub mod chains;
 pub mod chat;
 pub mod contract_chat;
 pub mod contract_daemon;
diff --git a/makima/src/server/mod.rs b/makima/src/server/mod.rs
index 12651d9..553797f 100644
--- a/makima/src/server/mod.rs
+++ b/makima/src/server/mod.rs
@@ -18,7 +18,7 @@ use tower_http::trace::TraceLayer;
 use utoipa::OpenApi;
 use utoipa_swagger_ui::SwaggerUi;
 
-use crate::server::handlers::{api_keys, chat, contract_chat, contract_daemon, contract_discuss, contracts, file_ws, files, history, listen, mesh, mesh_chat, mesh_daemon, mesh_merge, mesh_supervisor, mesh_ws, repository_history, speak, templates, transcript_analysis, users, versions};
+use crate::server::handlers::{api_keys, chains, chat, contract_chat, contract_daemon, contract_discuss, contracts, file_ws, files, history, listen, mesh, mesh_chat, mesh_daemon, mesh_merge, mesh_supervisor, mesh_ws, repository_history, speak, templates, transcript_analysis, users, versions};
 use crate::server::openapi::ApiDoc;
 use crate::server::state::SharedState;
 
@@ -214,6 +214,21 @@ pub fn make_router(state: SharedState) -> Router {
         )
         // Timeline endpoint (unified history for user)
         .route("/timeline", get(history::get_timeline))
+        // Chain endpoints (multi-contract orchestration)
+        .route(
+            "/chains",
+            get(chains::list_chains).post(chains::create_chain),
+        )
+        .route(
+            "/chains/{id}",
+            get(chains::get_chain)
+                .put(chains::update_chain)
+                .delete(chains::delete_chain),
+        )
+        .route("/chains/{id}/contracts", get(chains::get_chain_contracts))
+        .route("/chains/{id}/graph", get(chains::get_chain_graph))
+        .route("/chains/{id}/events", get(chains::get_chain_events))
+        .route("/chains/{id}/editor", get(chains::get_chain_editor))
         // Contract type templates (built-in only)
         .route("/contract-types", get(templates::list_contract_types))
         // Settings endpoints