opencode: lazily compose default layers

defaultLayer in several high-fan-in modules is currently composed at import
time. This makes module evaluation sensitive to transitive import order, even
though the layer graph itself is unchanged.

Wrap these compositions in Layer.suspend() so the same graph is built on
demand instead of during module load. This reduces init-order coupling and
makes import reordering for startup work safer.

I ran into this while trying to improve startup time by moving imports around.
No functional change intended.

packages/opencode/src/agent/agent.ts

@@ -393,11 +393,13 @@ export namespace Agent {
     }),
   )
 
-  export const defaultLayer = layer.pipe(
-    Layer.provide(Provider.defaultLayer),
-    Layer.provide(Auth.defaultLayer),
-    Layer.provide(Config.defaultLayer),
-    Layer.provide(Skill.defaultLayer),
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(
+      Layer.provide(Provider.defaultLayer),
+      Layer.provide(Auth.defaultLayer),
+      Layer.provide(Config.defaultLayer),
+      Layer.provide(Skill.defaultLayer),
+    ),
   )
 
   const { runPromise } = makeRuntime(Service, defaultLayer)

packages/opencode/src/command/index.ts

@@ -181,10 +181,8 @@ export namespace Command {
     }),
   )
 
-  export const defaultLayer = layer.pipe(
-    Layer.provide(Config.defaultLayer),
-    Layer.provide(MCP.defaultLayer),
-    Layer.provide(Skill.defaultLayer),
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(Layer.provide(Config.defaultLayer), Layer.provide(MCP.defaultLayer), Layer.provide(Skill.defaultLayer)),
   )
 
   const { runPromise } = makeRuntime(Service, defaultLayer)

packages/opencode/src/session/compaction.ts

@@ -380,17 +380,15 @@ When constructing the summary, try to stick to this template:
     }),
   )
 
-  export const defaultLayer = Layer.unwrap(
-    Effect.sync(() =>
-      layer.pipe(
-        Layer.provide(Provider.defaultLayer),
-        Layer.provide(Session.defaultLayer),
-        Layer.provide(SessionProcessor.defaultLayer),
-        Layer.provide(Agent.defaultLayer),
-        Layer.provide(Plugin.defaultLayer),
-        Layer.provide(Bus.layer),
-        Layer.provide(Config.defaultLayer),
-      ),
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(
+      Layer.provide(Provider.defaultLayer),
+      Layer.provide(Session.defaultLayer),
+      Layer.provide(SessionProcessor.defaultLayer),
+      Layer.provide(Agent.defaultLayer),
+      Layer.provide(Plugin.defaultLayer),
+      Layer.provide(Bus.layer),
+      Layer.provide(Config.defaultLayer),
     ),
   )
 

packages/opencode/src/session/index.ts

@@ -681,7 +681,9 @@ export namespace Session {
     }),
   )
 
-  export const defaultLayer = layer.pipe(Layer.provide(Bus.layer), Layer.provide(Config.defaultLayer))
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(Layer.provide(Bus.layer), Layer.provide(Config.defaultLayer)),
+  )
 
   const { runPromise } = makeRuntime(Service, defaultLayer)
 

packages/opencode/src/session/processor.ts

@@ -505,19 +505,17 @@ export namespace SessionProcessor {
     }),
   )
 
-  export const defaultLayer = Layer.unwrap(
-    Effect.sync(() =>
-      layer.pipe(
-        Layer.provide(Session.defaultLayer),
-        Layer.provide(Snapshot.defaultLayer),
-        Layer.provide(Agent.defaultLayer),
-        Layer.provide(LLM.defaultLayer),
-        Layer.provide(Permission.defaultLayer),
-        Layer.provide(Plugin.defaultLayer),
-        Layer.provide(SessionStatus.layer.pipe(Layer.provide(Bus.layer))),
-        Layer.provide(Bus.layer),
-        Layer.provide(Config.defaultLayer),
-      ),
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(
+      Layer.provide(Session.defaultLayer),
+      Layer.provide(Snapshot.defaultLayer),
+      Layer.provide(Agent.defaultLayer),
+      Layer.provide(LLM.defaultLayer),
+      Layer.provide(Permission.defaultLayer),
+      Layer.provide(Plugin.defaultLayer),
+      Layer.provide(SessionStatus.layer.pipe(Layer.provide(Bus.layer))),
+      Layer.provide(Bus.layer),
+      Layer.provide(Config.defaultLayer),
     ),
   )
 }

packages/opencode/src/session/prompt.ts

@@ -1709,28 +1709,26 @@ NOTE: At any point in time through this workflow you should feel free to ask the
     }),
   )
 
-  const defaultLayer = Layer.unwrap(
-    Effect.sync(() =>
-      layer.pipe(
-        Layer.provide(SessionStatus.layer),
-        Layer.provide(SessionCompaction.defaultLayer),
-        Layer.provide(SessionProcessor.defaultLayer),
-        Layer.provide(Command.defaultLayer),
-        Layer.provide(Permission.defaultLayer),
-        Layer.provide(MCP.defaultLayer),
-        Layer.provide(LSP.defaultLayer),
-        Layer.provide(FileTime.defaultLayer),
-        Layer.provide(ToolRegistry.defaultLayer),
-        Layer.provide(Truncate.layer),
-        Layer.provide(Provider.defaultLayer),
-        Layer.provide(Instruction.defaultLayer),
-        Layer.provide(AppFileSystem.defaultLayer),
-        Layer.provide(Plugin.defaultLayer),
-        Layer.provide(Session.defaultLayer),
-        Layer.provide(Agent.defaultLayer),
-        Layer.provide(Bus.layer),
-        Layer.provide(CrossSpawnSpawner.defaultLayer),
-      ),
+  const defaultLayer = Layer.suspend(() =>
+    layer.pipe(
+      Layer.provide(SessionStatus.layer),
+      Layer.provide(SessionCompaction.defaultLayer),
+      Layer.provide(SessionProcessor.defaultLayer),
+      Layer.provide(Command.defaultLayer),
+      Layer.provide(Permission.defaultLayer),
+      Layer.provide(MCP.defaultLayer),
+      Layer.provide(LSP.defaultLayer),
+      Layer.provide(FileTime.defaultLayer),
+      Layer.provide(ToolRegistry.defaultLayer),
+      Layer.provide(Truncate.layer),
+      Layer.provide(Provider.defaultLayer),
+      Layer.provide(Instruction.defaultLayer),
+      Layer.provide(AppFileSystem.defaultLayer),
+      Layer.provide(Plugin.defaultLayer),
+      Layer.provide(Session.defaultLayer),
+      Layer.provide(Agent.defaultLayer),
+      Layer.provide(Bus.layer),
+      Layer.provide(CrossSpawnSpawner.defaultLayer),
     ),
   )
   const { runPromise } = makeRuntime(Service, defaultLayer)

packages/opencode/src/session/revert.ts

@@ -148,15 +148,13 @@ export namespace SessionRevert {
     }),
   )
 
-  export const defaultLayer = Layer.unwrap(
-    Effect.sync(() =>
-      layer.pipe(
-        Layer.provide(Session.defaultLayer),
-        Layer.provide(Snapshot.defaultLayer),
-        Layer.provide(Storage.defaultLayer),
-        Layer.provide(Bus.layer),
-        Layer.provide(SessionSummary.defaultLayer),
-      ),
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(
+      Layer.provide(Session.defaultLayer),
+      Layer.provide(Snapshot.defaultLayer),
+      Layer.provide(Storage.defaultLayer),
+      Layer.provide(Bus.layer),
+      Layer.provide(SessionSummary.defaultLayer),
     ),
   )
 

packages/opencode/src/session/summary.ts

@@ -150,14 +150,12 @@ export namespace SessionSummary {
     }),
   )
 
-  export const defaultLayer = Layer.unwrap(
-    Effect.sync(() =>
-      layer.pipe(
-        Layer.provide(Session.defaultLayer),
-        Layer.provide(Snapshot.defaultLayer),
-        Layer.provide(Storage.defaultLayer),
-        Layer.provide(Bus.layer),
-      ),
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(
+      Layer.provide(Session.defaultLayer),
+      Layer.provide(Snapshot.defaultLayer),
+      Layer.provide(Storage.defaultLayer),
+      Layer.provide(Bus.layer),
     ),
   )
 

packages/opencode/src/share/share-next.ts

@@ -336,13 +336,15 @@ export namespace ShareNext {
     }),
   )
 
-  export const defaultLayer = layer.pipe(
-    Layer.provide(Bus.layer),
-    Layer.provide(Account.defaultLayer),
-    Layer.provide(Config.defaultLayer),
-    Layer.provide(FetchHttpClient.layer),
-    Layer.provide(Provider.defaultLayer),
-    Layer.provide(Session.defaultLayer),
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(
+      Layer.provide(Bus.layer),
+      Layer.provide(Account.defaultLayer),
+      Layer.provide(Config.defaultLayer),
+      Layer.provide(FetchHttpClient.layer),
+      Layer.provide(Provider.defaultLayer),
+      Layer.provide(Session.defaultLayer),
+    ),
   )
 
   const { runPromise } = makeRuntime(Service, defaultLayer)

packages/opencode/src/skill/index.ts

@@ -230,11 +230,13 @@ export namespace Skill {
     }),
   )
 
-  export const defaultLayer = layer.pipe(
-    Layer.provide(Discovery.defaultLayer),
-    Layer.provide(Config.defaultLayer),
-    Layer.provide(Bus.layer),
-    Layer.provide(AppFileSystem.defaultLayer),
+  export const defaultLayer = Layer.suspend(() =>
+    layer.pipe(
+      Layer.provide(Discovery.defaultLayer),
+      Layer.provide(Config.defaultLayer),
+      Layer.provide(Bus.layer),
+      Layer.provide(AppFileSystem.defaultLayer),
+    ),
   )
 
   export function fmt(list: Info[], opts: { verbose: boolean }) {