refactor(effect): build todowrite tool from Todo service (#20789)

Co-authored-by: Juan Pablo Carranza Hurtado <52012198+jpcarranza94@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

packages/opencode/src/session/todo.ts

@@ -82,7 +82,7 @@ export namespace Todo {
     }),
   )
 
-  const defaultLayer = layer.pipe(Layer.provide(Bus.layer))
+  export const defaultLayer = layer.pipe(Layer.provide(Bus.layer))
   const { runPromise } = makeRuntime(Service, defaultLayer)
 
   export async function update(input: { sessionID: SessionID; todos: Info[] }) {

packages/opencode/src/tool/registry.ts

@@ -34,6 +34,7 @@ import { InstanceState } from "@/effect/instance-state"
 import { makeRuntime } from "@/effect/run-service"
 import { Env } from "../env"
 import { Question } from "../question"
+import { Todo } from "../session/todo"
 
 export namespace ToolRegistry {
   const log = Log.create({ service: "tool.registry" })
@@ -56,7 +57,8 @@ export namespace ToolRegistry {
 
   export class Service extends ServiceMap.Service<Service, Interface>()("@opencode/ToolRegistry") {}
 
-  export const layer: Layer.Layer<Service, never, Config.Service | Plugin.Service | Question.Service> = Layer.effect(
+  export const layer: Layer.Layer<Service, never, Config.Service | Plugin.Service | Question.Service | Todo.Service> =
+    Layer.effect(
       Service,
       Effect.gen(function* () {
         const config = yield* Config.Service
@@ -140,7 +142,8 @@ export namespace ToolRegistry {
 
         const all = Effect.fn("ToolRegistry.all")(function* (custom: Tool.Info[]) {
           const cfg = yield* config.get()
-        const question = ["app", "cli", "desktop"].includes(Flag.OPENCODE_CLIENT) || Flag.OPENCODE_ENABLE_QUESTION_TOOL
+          const question =
+            ["app", "cli", "desktop"].includes(Flag.OPENCODE_CLIENT) || Flag.OPENCODE_ENABLE_QUESTION_TOOL
 
           return [
             invalid,
@@ -222,6 +225,7 @@ export namespace ToolRegistry {
         Layer.provide(Config.defaultLayer),
         Layer.provide(Plugin.defaultLayer),
         Layer.provide(Question.defaultLayer),
+        Layer.provide(Todo.defaultLayer),
       ),
     ),
   )

packages/opencode/src/tool/todo.ts

@@ -1,14 +1,26 @@
 import z from "zod"
+import { Effect } from "effect"
 import { Tool } from "./tool"
 import DESCRIPTION_WRITE from "./todowrite.txt"
 import { Todo } from "../session/todo"
 
-export const TodoWriteTool = Tool.define("todowrite", {
-  description: DESCRIPTION_WRITE,
-  parameters: z.object({
+const parameters = z.object({
   todos: z.array(z.object(Todo.Info.shape)).describe("The updated todo list"),
-  }),
-  async execute(params, ctx) {
+})
+
+type Metadata = {
+  todos: Todo.Info[]
+}
+
+export const TodoWriteTool = Tool.defineEffect<typeof parameters, Metadata, Todo.Service>(
+  "todowrite",
+  Effect.gen(function* () {
+    const todo = yield* Todo.Service
+
+    return {
+      description: DESCRIPTION_WRITE,
+      parameters,
+      async execute(params: z.infer<typeof parameters>, ctx: Tool.Context<Metadata>) {
         await ctx.ask({
           permission: "todowrite",
           patterns: ["*"],
@@ -16,10 +28,13 @@ export const TodoWriteTool = Tool.define("todowrite", {
           metadata: {},
         })
 
-    await Todo.update({
+        await todo
+          .update({
             sessionID: ctx.sessionID,
             todos: params.todos,
           })
+          .pipe(Effect.runPromise)
+
         return {
           title: `${params.todos.filter((x) => x.status !== "completed").length} todos`,
           output: JSON.stringify(params.todos, null, 2),
@@ -28,4 +43,6 @@ export const TodoWriteTool = Tool.define("todowrite", {
           },
         }
       },
-})
+    } satisfies Tool.Def<typeof parameters, Metadata>
+  }),
+)

packages/opencode/test/session/prompt-effect.test.ts

@@ -16,6 +16,7 @@ import { Provider as ProviderSvc } from "../../src/provider/provider"
 import type { Provider } from "../../src/provider/provider"
 import { ModelID, ProviderID } from "../../src/provider/schema"
 import { Question } from "../../src/question"
+import { Todo } from "../../src/session/todo"
 import { Session } from "../../src/session"
 import { LLM } from "../../src/session/llm"
 import { MessageV2 } from "../../src/session/message-v2"
@@ -162,7 +163,12 @@ function makeHttp() {
     status,
   ).pipe(Layer.provideMerge(infra))
   const question = Question.layer.pipe(Layer.provideMerge(deps))
-  const registry = ToolRegistry.layer.pipe(Layer.provideMerge(question), Layer.provideMerge(deps))
+  const todo = Todo.layer.pipe(Layer.provideMerge(deps))
+  const registry = ToolRegistry.layer.pipe(
+    Layer.provideMerge(todo),
+    Layer.provideMerge(question),
+    Layer.provideMerge(deps),
+  )
   const trunc = Truncate.layer.pipe(Layer.provideMerge(deps))
   const proc = SessionProcessor.layer.pipe(Layer.provideMerge(deps))
   const compact = SessionCompaction.layer.pipe(Layer.provideMerge(proc), Layer.provideMerge(deps))

packages/opencode/test/session/snapshot-tool-race.test.ts

@@ -39,6 +39,7 @@ import { Permission } from "../../src/permission"
 import { Plugin } from "../../src/plugin"
 import { Provider as ProviderSvc } from "../../src/provider/provider"
 import { Question } from "../../src/question"
+import { Todo } from "../../src/session/todo"
 import { SessionCompaction } from "../../src/session/compaction"
 import { Instruction } from "../../src/session/instruction"
 import { SessionProcessor } from "../../src/session/processor"
@@ -126,7 +127,12 @@ function makeHttp() {
     status,
   ).pipe(Layer.provideMerge(infra))
   const question = Question.layer.pipe(Layer.provideMerge(deps))
-  const registry = ToolRegistry.layer.pipe(Layer.provideMerge(question), Layer.provideMerge(deps))
+  const todo = Todo.layer.pipe(Layer.provideMerge(deps))
+  const registry = ToolRegistry.layer.pipe(
+    Layer.provideMerge(todo),
+    Layer.provideMerge(question),
+    Layer.provideMerge(deps),
+  )
   const trunc = Truncate.layer.pipe(Layer.provideMerge(deps))
   const proc = SessionProcessor.layer.pipe(Layer.provideMerge(deps))
   const compact = SessionCompaction.layer.pipe(Layer.provideMerge(proc), Layer.provideMerge(deps))

packages/opencode/test/tool/tool-define.test.ts

@@ -27,45 +27,37 @@ describe("Tool.define", () => {
     await tool.init()
     await tool.init()
 
-    // The original object's execute should never be overwritten
     expect(original.execute).toBe(originalExecute)
   })
 
   test("object-defined tool does not accumulate wrapper layers across init() calls", async () => {
-    let executeCalls = 0
+    let calls = 0
 
     const tool = Tool.define(
       "test-tool",
-      makeTool("test", () => executeCalls++),
+      makeTool("test", () => calls++),
     )
 
-    // Call init() many times to simulate many agentic steps
     for (let i = 0; i < 100; i++) {
       await tool.init()
     }
 
-    // Resolve the tool and call execute
     const resolved = await tool.init()
-    executeCalls = 0
+    calls = 0
 
-    // Capture the stack trace inside execute to measure wrapper depth
-    let stackInsideExecute = ""
-    const origExec = resolved.execute
+    let stack = ""
+    const exec = resolved.execute
     resolved.execute = async (args: any, ctx: any) => {
-      const result = await origExec.call(resolved, args, ctx)
-      const err = new Error()
-      stackInsideExecute = err.stack || ""
+      const result = await exec.call(resolved, args, ctx)
+      stack = new Error().stack || ""
       return result
     }
 
     await resolved.execute(defaultArgs, {} as any)
-    expect(executeCalls).toBe(1)
+    expect(calls).toBe(1)
 
-    // Count how many times tool.ts appears in the stack.
-    // With the fix: 1 wrapper layer (from the most recent init()).
-    // Without the fix: 101 wrapper layers from accumulated closures.
-    const toolTsFrames = stackInsideExecute.split("\n").filter((l) => l.includes("tool.ts")).length
-    expect(toolTsFrames).toBeLessThan(5)
+    const frames = stack.split("\n").filter((l) => l.includes("tool.ts")).length
+    expect(frames).toBeLessThan(5)
   })
 
   test("function-defined tool returns fresh objects and is unaffected", async () => {
@@ -74,7 +66,6 @@ describe("Tool.define", () => {
     const first = await tool.init()
     const second = await tool.init()
 
-    // Function-defined tools return distinct objects each time
     expect(first).not.toBe(second)
   })
 
@@ -84,7 +75,6 @@ describe("Tool.define", () => {
     const first = await tool.init()
     const second = await tool.init()
 
-    // Each init() should return a separate object so wrappers don't accumulate
     expect(first).not.toBe(second)
   })