fix: address multi-model code review feedback

- Remove dead else branch in `ENGINE_INSTALL_SPEC` conditional (constant
  is always truthy)
- Add `extras` field to `engine_started` telemetry event for debugging
- Update `ENGINE_INSTALL_SPEC` comment to reflect production usage
- Tighten concurrent startup test assertion to verify mutex coalescing
  (`ensureEngineCalls <= 2` instead of just `>= 1`)

Author: anandgupta42

packages/opencode/src/altimate/bridge/engine.ts

@@ -25,7 +25,8 @@ declare const OPENCODE_VERSION: string
 // Mutex to prevent concurrent ensureEngine/ensureUv calls from corrupting state
 let pendingEnsure: Promise<void> | null = null
 
-/** The pip install spec used by ensureEngine — exported for tests. */
+/** Pip extras spec for altimate-engine (e.g. "warehouses" → altimate-engine[warehouses]).
+ *  Used in ensureEngine install command and recorded in manifest for upgrade detection. */
 export const ENGINE_INSTALL_SPEC = "warehouses"
 
 interface Manifest {
@@ -199,9 +200,7 @@ async function ensureEngineImpl(): Promise<void> {
   const pythonPath = enginePythonPath()
   Log.Default.info("installing altimate-engine", { version: ALTIMATE_ENGINE_VERSION })
   try {
-    const spec = ENGINE_INSTALL_SPEC
-      ? `altimate-engine[${ENGINE_INSTALL_SPEC}]==${ALTIMATE_ENGINE_VERSION}`
-      : `altimate-engine==${ALTIMATE_ENGINE_VERSION}`
+    const spec = `altimate-engine[${ENGINE_INSTALL_SPEC}]==${ALTIMATE_ENGINE_VERSION}`
     execFileSync(uv, ["pip", "install", "--python", pythonPath, spec], { stdio: "pipe" })
   } catch (e: any) {
     Telemetry.track({
@@ -234,6 +233,7 @@ async function ensureEngineImpl(): Promise<void> {
     session_id: Telemetry.getContext().sessionId,
     engine_version: ALTIMATE_ENGINE_VERSION,
     python_version: pyVersion,
+    extras: ENGINE_INSTALL_SPEC,
     status: isUpgrade ? "upgraded" : "started",
     duration_ms: Date.now() - startTime,
   })

packages/opencode/src/altimate/telemetry/index.ts

@@ -153,6 +153,7 @@ export namespace Telemetry {
         session_id: string
         engine_version: string
         python_version: string
+        extras?: string
         status: "started" | "restarted" | "upgraded"
         duration_ms: number
       }

packages/opencode/test/bridge/client.test.ts

@@ -406,9 +406,11 @@ describe("Bridge.start integration", () => {
       expect(r.status).toBe("rejected")
     }
 
-    // ensureEngine should have been called, but not 3 times
-    // (mutex coalesces concurrent calls)
+    // The startup mutex should coalesce concurrent calls into a single
+    // ensureEngine invocation. In JS's single-threaded model, the first
+    // call sets pendingStart before any await, so subsequent calls join it.
     expect(ensureEngineCalls).toBeGreaterThanOrEqual(1)
+    expect(ensureEngineCalls).toBeLessThanOrEqual(2)
     Bridge.stop()
   })
 })