feat(core): attach global native tools (#30832)

packages/core/src/public/index.ts

@@ -3,6 +3,7 @@ export { Agent } from "./agent"
 export { Model } from "./model"
 export { OpenCode } from "./opencode"
 export { Session } from "./session"
+export { Tool } from "./tool"
 export { Location } from "./location"
 export { Prompt } from "../session/prompt"
 export { AbsolutePath } from "../schema"

packages/core/src/public/opencode.ts

@@ -9,10 +9,13 @@ import { SessionV2 } from "../session"
 import * as SessionExecutionLocal from "../session/execution/local"
 import { SessionProjector } from "../session/projector"
 import { SessionStore } from "../session/store"
+import { ApplicationTools } from "../tool/application-tools"
 import { Session } from "./session"
+import { Tool } from "./tool"
 
 export interface Interface {
   readonly sessions: Session.Interface
+  readonly tools: Tool.Service
 }
 
 /** Intentional public native API for Effect applications embedding OpenCode. */
@@ -28,13 +31,16 @@ const SessionsLayer = SessionV2.layer.pipe(
   Layer.provide(ProjectV2.defaultLayer),
   Layer.orDie,
 )
+const ApplicationToolsLayer = ApplicationTools.layer
 
 // TODO: Accept explicit storage so tests and embeddings can select disposable or application-owned persistence.
 export const layer = Layer.effect(
   Service,
   Effect.gen(function* () {
     const sessions = yield* SessionV2.Service
+    const tools = yield* ApplicationTools.Service
     return Service.of({
+      tools: { attach: tools.attach },
       sessions: {
         create: (input) =>
           sessions.create({
@@ -65,6 +71,6 @@ export const layer = Layer.effect(
       },
     })
   }),
-).pipe(Layer.provide(SessionsLayer))
+).pipe(Layer.provide(Layer.merge(ApplicationToolsLayer, SessionsLayer)))
 
 // TODO: Add OpenCode.create(...) as the Promise facade over the same native API semantics.

packages/core/src/public/tool.ts

@@ -0,0 +1,19 @@
+export * as Tool from "./tool"
+
+import { Effect, Scope } from "effect"
+import type { NativeTool } from "../tool/native"
+
+export { Failure, make } from "../tool/native"
+export type { Any, Content, Context, Executable } from "../tool/native"
+
+export interface Service {
+  /**
+   * Attach same-process tools to this OpenCode instance for the current Scope.
+   * Location tools with the same name take precedence where they are installed.
+   * Closing the Scope removes the tools immediately, so calls that have not
+   * started settling may fail because the tool is no longer available.
+   */
+  readonly attach: (
+    tools: Readonly<Record<string, NativeTool.Any>>,
+  ) => Effect.Effect<void, never, Scope.Scope>
+}