feat(lanes): let claude and codex lanes coexist at the same cwd

Repo/Adopt mode (POST /api/lanes/ensure) treated lanes.cwd as globally
unique, so adopting a path already driven by one CLI silently ignored a
different tool choice. Uniqueness moves to the composite (cwd, tool):
one directory can now back a claude lane and a codex lane side by side.

- server/db.js: drop the column-level UNIQUE on cwd, migrate existing
  DBs via table rebuild, add idx_lanes_cwd_tool.
- resolveLaneByCwd gains an optional tool filter; hook ingestion always
  pins to "claude" since Codex has no hook mechanism here, so a hook
  event never touches a codex lane sharing the path.
- POST /ensure resolves the existing owner by (cwd, tool) instead of
  cwd alone, so a different tool creates a sibling lane.
- LaneConsolePane's cwd-only lane lookups now also match tool, so a
  shared cwd doesn't attach a run to the wrong sibling lane.

Worktree mode is unaffected (already allocates a unique directory per
lane). docs/LANES.md and CLAUDE.md updated to describe the new
composite uniqueness.

CLAUDE.md

@@ -37,6 +37,7 @@ A **lane** is a durable unit of parallel agent work — one working directory, m
 - **Never build a git command as a shell string.** Lane git operations use `execFile("git", [...args])` with an explicit argument array (see `server/lib/worktree.js`'s `git()` helper), never a concatenated/interpolated string passed to a shell.
 - **A lane's `tool` is a lane fact, immutable, and never read from a request.** `lanes.tool` (`claude` | `codex`, default `claude`) is set by `createLane` only — it is deliberately absent from `PATCHABLE`, so no PATCH can flip the CLI under a live pane. Every spawn path (`POST /api/lanes/:id/start`, `POST /api/run`) takes the tool from the lane row and ignores whatever the body says; the run panel's Codex-only fields (`sandbox`, `approval`, `resumeLast`) are validated against the fixed allowlists in `server/lib/pty-run.js` before they reach an argv, and the bypass flags (`--dangerously-bypass-approvals-and-sandbox`, `--dangerously-bypass-hook-trust`) are never emitted. `GET /api/run/binary?tool=` resolves the probed binary name from that same allowlist — the query string reaches `which`.
 - **Adopted lanes are not destroyable.** A lane with `kind === "adopted"` may never have its worktree reset or removed; "removing" one only drops the dashboard's own record of it. This is enforced in code (`assertDestroyable`'s first check) — do not add a path that bypasses it.
+- **A `cwd` can back at most one lane per tool, not one lane overall.** Uniqueness is the composite `idx_lanes_cwd_tool` (`cwd`, `tool`), not `cwd` alone — Repo/Adopt mode (`POST /api/lanes/ensure`) lets the same directory carry a `claude` lane and a `codex` lane side by side, shown as two separate cards. `resolveLaneByCwd(cwd, tool)` takes an optional `tool` filter for exactly this; hook ingestion (`touchLaneFromHook`, `resolveLaneForWork`) always pins it to `"claude"` because Codex has no hook mechanism in this codebase, so a hook event must never touch a `codex` lane sharing the path. Worktree mode is unaffected — it already allocates a unique directory per lane.
 
 See `docs/LANES.md` for full guide: stage reporting, custom templates, lane actions, and the five node states.
 

client/src/components/run/LaneConsolePane.tsx

@@ -217,15 +217,22 @@ export function LaneConsolePane({
         // args.laneId — RunSetup always supplies this pane's laneId (a
         // required prop), which would otherwise silently start a run in the
         // wrong lane whenever the user types a cwd different from the one
-        // this pane currently shows.
-        const ownedLane = lanes.find((l) => l.cwd === effectiveCwd);
+        // this pane currently shows. A cwd can now back both a claude lane
+        // and a codex lane, so match this pane's own tool too (laneTool,
+        // which already defaults to "claude" when no lane is selected —
+        // the same default RunSetup renders) — otherwise the wrong sibling
+        // lane could be picked.
+        const ownedLane = lanes.find((l) => l.cwd === effectiveCwd && l.tool === laneTool);
         let targetLaneId: number;
         if (ownedLane) {
           targetLaneId = ownedLane.id;
           if (ownedLane.id !== laneId) onLaneIdChange(ownedLane.id);
         } else {
           try {
-            const ensureResult = await api.lanes.ensure({ cwd: effectiveCwd });
+            const ensureResult = await api.lanes.ensure({
+              cwd: effectiveCwd,
+              tool: laneTool,
+            });
             targetLaneId = ensureResult.lane.id;
             onLaneIdChange(ensureResult.lane.id);
             onLaneCreated(ensureResult.lane);
@@ -287,7 +294,7 @@ export function LaneConsolePane({
         setBusy(null);
       }
     },
-    [busy, t, lanes, laneId, onLaneIdChange, onLaneCreated, attachToRun, refreshList]
+    [busy, t, lanes, laneId, laneTool, onLaneIdChange, onLaneCreated, attachToRun, refreshList]
   );
 
   const onResumeFromHistory = useCallback(
@@ -301,10 +308,13 @@ export function LaneConsolePane({
 
         if (item.cwd) {
           const effectiveCwd = item.cwd;
-          let targetLaneId = lanes.find((l) => l.cwd === effectiveCwd)?.id;
+          // A cwd can now back both a claude lane and a codex lane — match
+          // this history item's own tool, the ground truth for which lane it
+          // belongs to, rather than an arbitrary lane at that cwd.
+          let targetLaneId = lanes.find((l) => l.cwd === effectiveCwd && l.tool === item.tool)?.id;
 
           if (!targetLaneId) {
-            const ensureResult = await api.lanes.ensure({ cwd: effectiveCwd });
+            const ensureResult = await api.lanes.ensure({ cwd: effectiveCwd, tool: item.tool });
             targetLaneId = ensureResult.lane.id;
             onLaneCreated(ensureResult.lane);
           }

docs/LANES.md

@@ -384,12 +384,12 @@ curl -X POST http://localhost:4820/api/lanes/ensure \
 }
 ```
 
-- If a lane already owns the `cwd`, returns that lane with `created: false` and HTTP `200`.
-- If the `cwd` is a subdirectory of an existing lane, returns the parent lane that owns it.
-- If no lane owns the `cwd`, creates an **adopted** lane and returns it with `created: true` and HTTP `201`.
+- If a lane already owns the `cwd` **for the requested `tool`**, returns that lane with `created: false` and HTTP `200`. `tool` (`claude` or `codex`, default `claude`) is part of the identity: adopting the same `cwd` with a different `tool` creates a second, sibling lane rather than adopting the existing one — one `cwd` can back at most one `claude` lane and one `codex` lane at a time. This applies to Repo/Adopt mode only; Worktree mode always gets its own directory.
+- If the `cwd` is a subdirectory of an existing lane with that same tool, returns the parent lane that owns it.
+- If no lane owns the `(cwd, tool)` pair, creates an **adopted** lane and returns it with `created: true` and HTTP `201`.
 - A relative or missing `cwd` returns `400 EBADCWD`.
 
-Two concurrent calls for the same path always yield one lane: the database's `UNIQUE` constraint on `lanes.cwd` decides the winner, and the loser re-reads and returns the winning lane.
+Two concurrent calls for the same `(cwd, tool)` pair always yield one lane: the database's composite `UNIQUE` index on `lanes(cwd, tool)` decides the winner, and the loser re-reads and returns the winning lane.
 
 ### Reading a lane's working copy: `GET /api/lanes/:id/git`
 

server/__tests__/lanes-api.test.js

@@ -928,6 +928,49 @@ describe("detection attributes work to the lane the work touched", () => {
     await request("DELETE", `/api/lanes/${worked.body.lane.id}`);
     await request("DELETE", `/api/lanes/${session.body.lane.id}`);
   });
+
+  it("a hook event at a shared cwd only touches the claude lane, never the codex lane", async () => {
+    const claudeLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/lane-dual-tool",
+      tool: "claude",
+    });
+    const codexLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/lane-dual-tool",
+      tool: "codex",
+    });
+    assert.notEqual(claudeLane.body.lane.id, codexLane.body.lane.id);
+
+    await request("POST", "/api/hooks/event", {
+      hook_type: "PostToolUse",
+      data: {
+        session_id: "sess-dual-tool",
+        cwd: "/tmp/lane-dual-tool",
+        tool_name: "Bash",
+        tool_input: { command: "npm run test:server" },
+      },
+    });
+
+    assert.equal(
+      (await request("GET", `/api/lanes/${claudeLane.body.lane.id}`)).body.lane.detected_stage,
+      "tests"
+    );
+    assert.equal(
+      (await request("GET", `/api/lanes/${claudeLane.body.lane.id}`)).body.lane.session_id,
+      "sess-dual-tool"
+    );
+    assert.equal(
+      (await request("GET", `/api/lanes/${codexLane.body.lane.id}`)).body.lane.detected_stage,
+      null,
+      "the codex lane sharing this cwd must not absorb a claude hook event"
+    );
+    assert.equal(
+      (await request("GET", `/api/lanes/${codexLane.body.lane.id}`)).body.lane.session_id,
+      null
+    );
+
+    await request("DELETE", `/api/lanes/${claudeLane.body.lane.id}`);
+    await request("DELETE", `/api/lanes/${codexLane.body.lane.id}`);
+  });
 });
 
 describe("GET /:id/ci/status", () => {
@@ -1007,4 +1050,250 @@ describe("/api/lanes tool tests", () => {
     assert.equal(res.status, 400);
     assert.equal(res.body.error.code, "EBADTOOL");
   });
+
+  it("POST /api/lanes/ensure creates a second lane for the same cwd on a different tool", async () => {
+    const first = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/claude-lane",
+      tool: "claude",
+    });
+    assert.equal(first.status, 201);
+
+    const second = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/claude-lane",
+      tool: "codex",
+    });
+    assert.equal(second.status, 201);
+    assert.equal(second.body.created, true);
+    assert.notEqual(second.body.lane.id, first.body.lane.id);
+    assert.equal(second.body.lane.cwd, first.body.lane.cwd);
+    assert.equal(second.body.lane.tool, "codex");
+    assert.equal(first.body.lane.tool, "claude");
+  });
+
+  it("POST /api/lanes/ensure re-ensuring the same (cwd, tool) pair is a no-op", async () => {
+    const first = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/claude-lane-2",
+      tool: "claude",
+    });
+    assert.equal(first.status, 201);
+
+    const second = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/claude-lane-2",
+      tool: "claude",
+    });
+    assert.equal(second.status, 200);
+    assert.equal(second.body.created, false);
+    assert.equal(second.body.lane.id, first.body.lane.id);
+  });
+
+  it("POST /api/lanes/ensure re-ensuring with the same tool is a no-op", async () => {
+    const first = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/same-tool-lane",
+      tool: "codex",
+    });
+    assert.equal(first.status, 201);
+
+    const second = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/same-tool-lane",
+      tool: "codex",
+    });
+    assert.equal(second.status, 200);
+    assert.equal(second.body.created, false);
+    assert.equal(second.body.lane.tool, "codex");
+  });
+
+  it("POST /api/lanes/ensure defaults to 'claude' tool when tool is not specified", async () => {
+    const res = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/default-tool-lane",
+    });
+    assert.equal(res.status, 201);
+    assert.equal(res.body.lane.tool, "claude");
+  });
+
+  it("GET /api/lanes returns both lanes for a shared cwd with distinct IDs and tools", async () => {
+    const claudeLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-list-cwd",
+      tool: "claude",
+    });
+    const codexLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-list-cwd",
+      tool: "codex",
+    });
+    const claudeId = claudeLane.body.lane.id;
+    const codexId = codexLane.body.lane.id;
+
+    const list = await request("GET", "/api/lanes");
+    assert.equal(list.status, 200);
+
+    const dualCwdLanes = list.body.lanes.filter((l) => l.cwd === "/tmp/dual-list-cwd");
+    assert.equal(dualCwdLanes.length, 2, "expected both lanes to appear in the list");
+
+    const found = {
+      claude: dualCwdLanes.find((l) => l.tool === "claude"),
+      codex: dualCwdLanes.find((l) => l.tool === "codex"),
+    };
+    assert.ok(found.claude, "claude lane must be in the list");
+    assert.ok(found.codex, "codex lane must be in the list");
+    assert.equal(found.claude.id, claudeId);
+    assert.equal(found.codex.id, codexId);
+    assert.notEqual(found.claude.id, found.codex.id);
+
+    await request("DELETE", `/api/lanes/${claudeId}`);
+    await request("DELETE", `/api/lanes/${codexId}`);
+  });
+
+  it("DELETE one lane of a (cwd, tool) pair leaves the sibling lane untouched", async () => {
+    const claudeLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-delete-cwd",
+      tool: "claude",
+    });
+    const codexLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-delete-cwd",
+      tool: "codex",
+    });
+    const claudeId = claudeLane.body.lane.id;
+    const codexId = codexLane.body.lane.id;
+
+    // Delete the codex lane
+    const deleteRes = await request("DELETE", `/api/lanes/${codexId}`);
+    assert.equal(deleteRes.status, 200);
+
+    // Verify the codex lane is gone
+    assert.equal((await request("GET", `/api/lanes/${codexId}`)).status, 404);
+
+    // Verify the claude lane still exists and is untouched
+    const claudeAfterDelete = await request("GET", `/api/lanes/${claudeId}`);
+    assert.equal(claudeAfterDelete.status, 200);
+    assert.equal(claudeAfterDelete.body.lane.tool, "claude");
+    assert.equal(claudeAfterDelete.body.lane.cwd, "/tmp/dual-delete-cwd");
+
+    await request("DELETE", `/api/lanes/${claudeId}`);
+  });
+
+  it("POST /api/lanes/ensure rejects an invalid tool even when two valid lanes already exist at that cwd", async () => {
+    const claudeLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-invalid-tool-cwd",
+      tool: "claude",
+    });
+    await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-invalid-tool-cwd",
+      tool: "codex",
+    });
+
+    const badRes = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-invalid-tool-cwd",
+      tool: "cursor", // invalid
+    });
+    assert.equal(badRes.status, 400);
+    assert.equal(badRes.body.error.code, "EBADTOOL");
+
+    await request("DELETE", `/api/lanes/${claudeLane.body.lane.id}`);
+  });
+
+  it("POST /api/lanes/worktree with tool parameter creates a lane with the specified tool", async () => {
+    const sourceRepo = require("path").join(
+      require("os").tmpdir(),
+      `ccam-worktree-src-${Date.now()}`
+    );
+    const fs = require("fs");
+    fs.mkdirSync(sourceRepo, { recursive: true });
+    require("child_process").execSync("git init", { cwd: sourceRepo });
+
+    const res = await request("POST", "/api/lanes/worktree", {
+      sourceRepo,
+      slug: "test-codex-worktree",
+      tool: "codex",
+    });
+
+    assert.equal(res.status, 202, "worktree create should return 202 Accepted");
+    assert.equal(res.body.lane.tool, "codex");
+
+    // Cleanup
+    fs.rmSync(sourceRepo, { recursive: true, force: true });
+
+    // Note: the actual provisioning happens asynchronously, so we don't verify it here.
+    // Just verify the lane was created with the right tool.
+    if (res.body.lane.id) {
+      await request("DELETE", `/api/lanes/${res.body.lane.id}`);
+    }
+  });
+
+  it("POST /api/lanes/worktree defaults to 'claude' tool when tool is not specified", async () => {
+    const sourceRepo = require("path").join(
+      require("os").tmpdir(),
+      `ccam-worktree-default-${Date.now()}`
+    );
+    const fs = require("fs");
+    fs.mkdirSync(sourceRepo, { recursive: true });
+    require("child_process").execSync("git init", { cwd: sourceRepo });
+
+    const res = await request("POST", "/api/lanes/worktree", {
+      sourceRepo,
+      slug: "test-default-worktree",
+    });
+
+    assert.equal(res.status, 202);
+    assert.equal(res.body.lane.tool, "claude");
+
+    // Cleanup
+    fs.rmSync(sourceRepo, { recursive: true, force: true });
+
+    if (res.body.lane.id) {
+      await request("DELETE", `/api/lanes/${res.body.lane.id}`);
+    }
+  });
+
+  it("POST /api/lanes/ensure with tool parameter preserves title on re-ensure", async () => {
+    const first = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/ensure-title-cwd",
+      tool: "claude",
+      title: "My Claude Lane",
+    });
+    assert.equal(first.body.lane.title, "My Claude Lane");
+
+    // Re-ensure without title should preserve the original
+    const second = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/ensure-title-cwd",
+      tool: "claude",
+    });
+    assert.equal(second.status, 200);
+    assert.equal(second.body.created, false);
+    assert.equal(second.body.lane.title, "My Claude Lane");
+
+    await request("DELETE", `/api/lanes/${first.body.lane.id}`);
+  });
+
+  it("two lanes at the same cwd with different tools have independent session_id tracking", async () => {
+    const claudeLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-session-cwd",
+      tool: "claude",
+    });
+    const codexLane = await request("POST", "/api/lanes/ensure", {
+      cwd: "/tmp/dual-session-cwd",
+      tool: "codex",
+    });
+
+    const claudeId = claudeLane.body.lane.id;
+    const codexId = codexLane.body.lane.id;
+
+    // Simulate a hook event that should only update the claude lane
+    await request("POST", "/api/hooks/event", {
+      hook_type: "PostToolUse",
+      data: {
+        session_id: "sess-dual-session-test",
+        cwd: "/tmp/dual-session-cwd",
+        tool_name: "Bash",
+        tool_input: { command: "npm run test:server" },
+      },
+    });
+
+    const claudeAfter = await request("GET", `/api/lanes/${claudeId}`);
+    const codexAfter = await request("GET", `/api/lanes/${codexId}`);
+
+    assert.equal(claudeAfter.body.lane.session_id, "sess-dual-session-test");
+    assert.equal(codexAfter.body.lane.session_id, null);
+
+    await request("DELETE", `/api/lanes/${claudeId}`);
+    await request("DELETE", `/api/lanes/${codexId}`);
+  });
 });

server/__tests__/lanes-cwd-unique-rebuild.test.js

@@ -0,0 +1,127 @@
+/**
+ * @file Verifies the legacy `lanes_new` rebuild in db.js (triggered when the
+ * lanes table's stored SQL still contains the old single-column
+ * `cwd TEXT NOT NULL UNIQUE`) drops that constraint in favor of the composite
+ * `idx_lanes_cwd_tool` unique index, preserves existing rows, and recreates
+ * idx_lanes_session / idx_lanes_slot.
+ *
+ * Regression coverage for the codex+claude coexistence feature: a cwd used to
+ * back at most one lane; now one cwd can back a `claude` lane and a `codex`
+ * lane at once, which requires dropping the old column-level UNIQUE.
+ *
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+const { describe, it, before, after } = require("node:test");
+const assert = require("node:assert/strict");
+const path = require("path");
+const fs = require("fs");
+const os = require("os");
+const Database = require("better-sqlite3");
+
+let TEST_DB;
+
+before(() => {
+  TEST_DB = path.join(os.tmpdir(), `dashboard-lanes-legacy-${Date.now()}-${process.pid}.db`);
+  process.env.DASHBOARD_DB_PATH = TEST_DB;
+
+  // Hand-build a legacy lanes table using the original single-column UNIQUE
+  // cwd, none of the columns added by later migrations (kind, source_repo,
+  // base_branch, slug, tool, detected_*, slot, ports, active_feature_id).
+  // This is the exact shape the "cwd TEXT NOT NULL UNIQUE" detector is
+  // looking for.
+  const raw = new Database(TEST_DB);
+  raw.pragma("foreign_keys = OFF");
+  raw.exec(`
+    CREATE TABLE lanes (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      title TEXT NOT NULL DEFAULT '',
+      cwd TEXT NOT NULL UNIQUE,
+      branch TEXT,
+      pipeline TEXT NOT NULL DEFAULT 'default',
+      session_id TEXT,
+      run_id TEXT,
+      stage TEXT NOT NULL DEFAULT 'idle',
+      stage_since TEXT,
+      status TEXT NOT NULL DEFAULT 'idle',
+      gate_decision TEXT,
+      ci_status TEXT,
+      needs_action TEXT,
+      links TEXT NOT NULL DEFAULT '{}',
+      stages TEXT NOT NULL DEFAULT '{}',
+      notes TEXT,
+      created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+      updated_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
+    );
+  `);
+  raw
+    .prepare("INSERT INTO lanes (title, cwd) VALUES (?, ?)")
+    .run("legacy lane", "/tmp/legacy-lane-cwd");
+  raw.close();
+});
+
+after(() => {
+  try {
+    delete require.cache[require.resolve("../db")];
+  } catch {}
+  for (const suffix of ["", "-wal", "-shm"]) {
+    try {
+      fs.unlinkSync(TEST_DB + suffix);
+    } catch {}
+  }
+});
+
+describe("legacy lanes_new rebuild (pre-tool, single-column cwd UNIQUE DB)", () => {
+  it("loads db.js against the legacy DB without throwing", () => {
+    delete require.cache[require.resolve("../db")];
+    assert.doesNotThrow(() => require("../db"));
+  });
+
+  it("preserves the pre-existing lane row and defaults tool to claude", () => {
+    const { db } = require("../db");
+    const row = db.prepare("SELECT * FROM lanes WHERE cwd = ?").get("/tmp/legacy-lane-cwd");
+    assert.ok(row, "expected the legacy lane row to survive the rebuild");
+    assert.equal(row.title, "legacy lane");
+    assert.equal(row.tool, "claude");
+  });
+
+  it("recreates idx_lanes_session and idx_lanes_slot", () => {
+    const { db } = require("../db");
+    for (const name of ["idx_lanes_session", "idx_lanes_slot"]) {
+      const idx = db
+        .prepare("SELECT name FROM sqlite_master WHERE type = 'index' AND name = ?")
+        .get(name);
+      assert.ok(idx, `expected ${name} to exist after the rebuild`);
+    }
+  });
+
+  it("drops the single-column cwd UNIQUE, allowing a second lane at the same cwd on a different tool", () => {
+    const { db } = require("../db");
+    const legacy = db.prepare("SELECT id FROM lanes WHERE cwd = ?").get("/tmp/legacy-lane-cwd");
+    assert.doesNotThrow(() => {
+      db.prepare("INSERT INTO lanes (title, cwd, tool) VALUES (?, ?, ?)").run(
+        "codex sibling",
+        "/tmp/legacy-lane-cwd",
+        "codex"
+      );
+    });
+    const both = db
+      .prepare("SELECT id, tool FROM lanes WHERE cwd = ? ORDER BY id")
+      .all("/tmp/legacy-lane-cwd");
+    assert.equal(both.length, 2);
+    assert.equal(both[0].id, legacy.id);
+    assert.equal(both[0].tool, "claude");
+    assert.equal(both[1].tool, "codex");
+  });
+
+  it("still enforces uniqueness within the same (cwd, tool) pair", () => {
+    const { db } = require("../db");
+    assert.throws(() => {
+      db.prepare("INSERT INTO lanes (title, cwd, tool) VALUES (?, ?, ?)").run(
+        "duplicate claude",
+        "/tmp/legacy-lane-cwd",
+        "claude"
+      );
+    }, /UNIQUE/);
+  });
+});

server/db.js

@@ -414,7 +414,7 @@ db.exec(`
   CREATE TABLE IF NOT EXISTS lanes (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
     title TEXT NOT NULL DEFAULT '',
-    cwd TEXT NOT NULL UNIQUE,
+    cwd TEXT NOT NULL,
     branch TEXT,
     pipeline TEXT NOT NULL DEFAULT 'default',
     session_id TEXT,
@@ -585,6 +585,74 @@ try {
   ).run();
 }
 
+// Migrate: cwd used to be single-column UNIQUE (one directory = one lane).
+// Codex and Claude Code lanes now coexist at the same adopted path, so
+// uniqueness moves to (cwd, tool) instead. SQLite can't ALTER TABLE to drop a
+// column-level UNIQUE, so rebuild the table when the old constraint is still
+// there — same rename-copy-drop pattern as the `agents` status rebuild above.
+// A fresh DB already gets the new column definition from CREATE TABLE.
+{
+  const laneTableInfo = db
+    .prepare("SELECT sql FROM sqlite_master WHERE type='table' AND name='lanes'")
+    .get();
+  if (
+    laneTableInfo &&
+    laneTableInfo.sql &&
+    laneTableInfo.sql.includes("cwd TEXT NOT NULL UNIQUE")
+  ) {
+    db.exec(`
+      PRAGMA foreign_keys = OFF;
+      BEGIN;
+      CREATE TABLE lanes_new (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        title TEXT NOT NULL DEFAULT '',
+        cwd TEXT NOT NULL,
+        branch TEXT,
+        pipeline TEXT NOT NULL DEFAULT 'default',
+        session_id TEXT,
+        run_id TEXT,
+        stage TEXT NOT NULL DEFAULT 'idle',
+        stage_since TEXT,
+        status TEXT NOT NULL DEFAULT 'idle',
+        gate_decision TEXT,
+        ci_status TEXT,
+        needs_action TEXT,
+        links TEXT NOT NULL DEFAULT '{}',
+        stages TEXT NOT NULL DEFAULT '{}',
+        notes TEXT,
+        created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+        updated_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
+        kind TEXT NOT NULL DEFAULT 'adopted',
+        source_repo TEXT,
+        base_branch TEXT,
+        slug TEXT,
+        tool TEXT NOT NULL DEFAULT 'claude',
+        detected_stage TEXT,
+        detected_signal TEXT,
+        detected_at TEXT,
+        slot INTEGER,
+        ports TEXT NOT NULL DEFAULT '{}',
+        active_feature_id INTEGER REFERENCES lane_features(id) ON DELETE SET NULL
+      );
+      INSERT INTO lanes_new SELECT
+        id, title, cwd, branch, pipeline, session_id, run_id, stage, stage_since,
+        status, gate_decision, ci_status, needs_action, links, stages, notes,
+        created_at, updated_at, kind, source_repo, base_branch, slug, tool,
+        detected_stage, detected_signal, detected_at, slot, ports, active_feature_id
+      FROM lanes;
+      DROP TABLE lanes;
+      ALTER TABLE lanes_new RENAME TO lanes;
+      COMMIT;
+      PRAGMA foreign_keys = ON;
+    `);
+    db.exec(`
+      CREATE INDEX IF NOT EXISTS idx_lanes_session ON lanes(session_id);
+      CREATE UNIQUE INDEX IF NOT EXISTS idx_lanes_slot ON lanes(slot) WHERE slot IS NOT NULL;
+    `);
+  }
+}
+db.prepare("CREATE UNIQUE INDEX IF NOT EXISTS idx_lanes_cwd_tool ON lanes(cwd, tool)").run();
+
 // Migrate: link agent rows to a workflow run. Workflow inner-agents are already
 // ingested as subagents (same subagents/ dir); these columns add the grouping +
 // phase that the run journal provides. Additive, safe on existing DBs.

server/lib/lanes.js

@@ -401,12 +401,20 @@ function recoverInterruptedProvisioning() {
 /**
  * Longest path-boundary prefix match. `/tmp/wt` must NOT capture
  * `/tmp/wt-sibling`, and a nested lane must beat its parent.
+ *
+ * `tool`, when given, narrows the candidates to that lane's tool before the
+ * prefix comparison — needed now that one cwd can back both a `claude` lane
+ * and a `codex` lane (see `idx_lanes_cwd_tool`). Omitted, it matches any tool,
+ * which stays correct for callers that already know they hold the lane's own
+ * cwd (there's only ever one match for that exact path per tool, and this
+ * caller shape doesn't care which).
  */
-function resolveLaneByCwd(cwd) {
+function resolveLaneByCwd(cwd, tool) {
   if (!cwd || typeof cwd !== "string") return null;
   const target = cwd.replace(/\/+$/, "");
   let best = null;
   for (const lane of listLanes()) {
+    if (tool && lane.tool !== tool) continue;
     const base = lane.cwd.replace(/\/+$/, "");
     if (target === base || target.startsWith(`${base}/`)) {
       if (!best || base.length > best.cwd.length) best = lane;
@@ -446,14 +454,18 @@ function absolutePathsIn(toolInput) {
  *
  * Only stage inference uses this. `session_id` and `needs_action` stay on the
  * session's own lane, because those genuinely are session-scoped facts.
+ *
+ * Hooks-only, and hooks are only ever emitted by the Claude Code CLI (Codex
+ * has no equivalent hook mechanism here) — so both lookups are pinned to the
+ * `claude` lane at each path, never the `codex` one that might share it.
  */
 function resolveLaneForWork(sessionCwd, toolInput) {
   let best = null;
   for (const candidate of absolutePathsIn(toolInput)) {
-    const lane = resolveLaneByCwd(candidate);
+    const lane = resolveLaneByCwd(candidate, "claude");
     if (lane && (!best || lane.cwd.length > best.cwd.length)) best = lane;
   }
-  return best || resolveLaneByCwd(sessionCwd);
+  return best || resolveLaneByCwd(sessionCwd, "claude");
 }
 
 function classifyLiveness({ status, stage, ageSec }, deadSec = DEAD_SEC) {

server/routes/hooks.js

@@ -169,7 +169,9 @@ const LANE_DONE_HOOKS = new Set(["Stop", "SessionEnd"]);
 function touchLaneFromHook(hookType, data) {
   try {
     if (!data || !data.cwd) return;
-    const lane = lanesLib.resolveLaneByCwd(data.cwd);
+    // Hooks are only ever emitted by the Claude Code CLI, so pin to the
+    // `claude` lane at this cwd — never the `codex` lane that might share it.
+    const lane = lanesLib.resolveLaneByCwd(data.cwd, "claude");
     if (!lane) return;
 
     // Infer the lane's stage from this one tool event, best-effort. A real

server/routes/lanes.js

@@ -265,7 +265,11 @@ router.post("/ensure", sameOriginGuard, (req, res) => {
     return res.status(400).json({ error: { code: "EBADTOOL", message: "unknown tool" } });
   }
 
-  const owner = lanesLib.resolveLaneByCwd(cwd);
+  // A cwd can now back one lane per tool (idx_lanes_cwd_tool) — "does a lane
+  // already own this (cwd, tool) pair" is the real question, so a request for
+  // a different tool than an existing lane at this cwd falls through to
+  // creating that tool's own lane instead of adopting the wrong one.
+  const owner = lanesLib.resolveLaneByCwd(cwd, body.tool || "claude");
   if (owner) {
     // First-write wins on the title: an ensure-with-title on an existing lane
     // is how callers like Sagi adopt the lane, so don't clobber a real title
@@ -292,7 +296,7 @@ router.post("/ensure", sameOriginGuard, (req, res) => {
     // The cwd UNIQUE constraint is the arbiter: someone else won the race, so
     // re-read and return THEIR lane rather than reporting a conflict.
     if (err.code === "SQLITE_CONSTRAINT_UNIQUE" || String(err.message).includes("UNIQUE")) {
-      const winner = lanesLib.resolveLaneByCwd(cwd);
+      const winner = lanesLib.resolveLaneByCwd(cwd, body.tool || "claude");
       if (winner) return res.json({ lane: payload(winner), created: false });
     }
     return res.status(500).json({ error: { code: err.code, message: err.message } });