fix(core): tighten plan switch reminder copy

Rewrite enter and leave synthetics to state the read-only constraint
and its removal without extra workflow instructions.

packages/core/src/config/plugin/source.ts

@@ -4,7 +4,7 @@ import { Directory, Document, type Entry } from "@opencode-ai/schema/config"
 import { ConfigPlugin } from "@opencode-ai/schema/config/plugin"
 import { FSUtil } from "@opencode-ai/util/fs-util"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
-import { Context, Effect, Layer, Option, PubSub, Schema, Scope, Stream } from "effect"
+import { Context, Effect, Layer, Option, PubSub, Scope, Stream } from "effect"
 import path from "path"
 import { fileURLToPath } from "url"
 import { Config } from "../../config"
@@ -154,12 +154,6 @@ const scan = Effect.fn("ConfigPluginSource.scan")(function* (
 })
 
 const sourceDirectories = ["plugin", "plugins"] as const
-const Package = Schema.Struct({
-  exports: Schema.optional(Schema.Unknown),
-  module: Schema.optional(Schema.Unknown),
-  main: Schema.optional(Schema.Unknown),
-})
-const decodePackage = Schema.decodeUnknownOption(Package)
 
 function discoverDirectory(fs: FSUtil.Interface, directory: string) {
   return Effect.gen(function* () {
@@ -172,38 +166,7 @@ function discoverDirectory(fs: FSUtil.Interface, directory: string) {
         symlink: true,
       })
       .pipe(Effect.orElseSucceed(() => []))
-    const children = yield* fs
-      .scan(`{${sourceDirectories.join(",")}}/*`, {
-        cwd: directory,
-        absolute: true,
-        include: "all",
-        dot: true,
-        symlink: true,
-      })
-      .pipe(Effect.orElseSucceed(() => []))
-    const directories = yield* Effect.filter(children.sort(), fs.isDir)
-    const packages = yield* Effect.forEach(directories, (child) => discoverPackage(fs, child))
-    return [...files.sort(), ...packages.filter((target): target is string => typeof target === "string")].map(
-      (target): Operation => ({ type: "add", target, options: {} }),
-    )
-  })
-}
-
-function discoverPackage(fs: FSUtil.Interface, directory: string) {
-  return Effect.gen(function* () {
-    const manifest = yield* fs
-      .readJson(path.join(directory, "package.json"))
-      .pipe(Effect.map(decodePackage), Effect.orElseSucceed(Option.none))
-    const configured = Option.isSome(manifest)
-      ? [manifest.value.exports, manifest.value.module, manifest.value.main].filter(
-          (entry): entry is string => typeof entry === "string",
-        )
-      : []
-    const target = yield* Effect.findFirst(
-      [...configured, "index.ts", "index.js"].map((entry) => path.resolve(directory, entry)),
-      fs.isFile,
-    )
-    return Option.getOrUndefined(target)
+    return files.sort().map((target): Operation => ({ type: "add", target, options: {} }))
   })
 }
 

packages/core/src/plugin/agent.ts

@@ -101,16 +101,6 @@ export const Plugin = define({
         item.permissions.push({ action: "question", resource: "*", effect: "allow" })
       })
 
-      draft.update(Agent.ID.make("plan"), (item) => {
-        item.name = Agent.Name.make("Plan")
-        item.description = "Plan mode. Disallows all edit tools."
-        item.mode = "primary"
-        item.permissions.push(
-          { action: "question", resource: "*", effect: "allow" },
-          { action: "edit", resource: "*", effect: "deny" },
-        )
-      })
-
       draft.update(Agent.ID.make("general"), (item) => {
         item.name = Agent.Name.make("General")
         item.description =

packages/core/src/plugin/internal.ts

@@ -60,6 +60,7 @@ import { WellKnown } from "../wellknown"
 import { WriteTool } from "../tool/plugin/write"
 import { AgentPlugin } from "./agent"
 import { CommandPlugin } from "./command"
+import { PlanPlugin } from "./plan"
 import { ModelsDevPlugin } from "./models-dev"
 import { ProviderPlugins } from "./provider"
 import { WebSearchPlugins } from "./websearch"
@@ -192,6 +193,7 @@ export type InternalPlugin = Plugin<Requirements | Scope.Scope>
 const pre = [
   WellKnownPlugin.Plugin,
   AgentPlugin.Plugin,
+  PlanPlugin.Plugin,
   CommandPlugin.Plugin,
   SkillPlugin.Plugin,
   ...SystemPromptPlugin.Plugins,

packages/core/src/plugin/plan.ts

@@ -0,0 +1,55 @@
+export * as PlanPlugin from "./plan"
+
+import { ToolFailure } from "@opencode-ai/ai"
+import { define } from "@opencode-ai/plugin/effect/plugin"
+import { Effect, Stream } from "effect"
+import { Agent } from "../agent"
+
+const plan = Agent.ID.make("plan")
+
+const enter = `<system-reminder>
+You are in Plan mode. This is a READ-ONLY environment. You are not allowed to edit files, and you may not ask a subagent to edit them either.
+</system-reminder>`
+
+const leave = `<system-reminder>
+You are no longer in Plan mode. The previous read-only restrictions no longer apply. You may edit files again.
+</system-reminder>`
+
+export const Plugin = define({
+  id: "opencode.plan",
+  effect: Effect.fn(function* (ctx) {
+    yield* ctx.agent.transform((draft) => {
+      draft.update(plan, (item) => {
+        item.name = Agent.Name.make("Plan")
+        item.description = "Read-only agent for exploring the codebase and planning work before implementation."
+        item.mode = "primary"
+        item.permissions.push({ action: "question", resource: "*", effect: "allow" })
+      })
+    })
+
+    yield* ctx.tool.hook("execute.before", (event) => {
+      if (event.agent !== plan) return Effect.void
+      if (event.tool !== "edit" && event.tool !== "write" && event.tool !== "patch") return Effect.void
+      return new ToolFailure({
+        message: `Cannot use ${event.tool} in Plan mode. You are in a read-only mode and must not modify files.`,
+      })
+    })
+
+    yield* ctx.event.subscribe().pipe(
+      Stream.filter((event) => event.type === "session.agent.selected"),
+      Stream.runForEach((event) => {
+        if (event.data.agent === event.data.previous) return Effect.void
+        const text = event.data.agent === plan ? enter : event.data.previous === plan ? leave : undefined
+        if (!text) return Effect.void
+        return ctx.session
+          .synthetic({
+            sessionID: event.data.sessionID,
+            text,
+            resume: false,
+          })
+          .pipe(Effect.catch(() => Effect.void))
+      }),
+      Effect.forkScoped({ startImmediately: true }),
+    )
+  }),
+})

packages/core/test/agent.test.ts

@@ -165,7 +165,6 @@ describe("Agent", () => {
         "compaction",
         "explore",
         "general",
-        "plan",
         "summary",
         "title",
       ])

packages/core/test/config/plugin.test.ts

@@ -168,69 +168,6 @@ describe("PluginSupervisor config", () => {
     ),
   )
 
-  it.live("loads auto-discovered plugin packages from package metadata", () =>
-    withLocation(
-      undefined,
-      Effect.gen(function* () {
-        yield* ready()
-        const plugins = yield* Plugin.Service
-        expect((yield* plugins.list()).map((plugin) => String(plugin.id))).toContain("package-metadata")
-      }),
-      false,
-      async (directory) => {
-        const plugin = path.join(directory, ".opencode", "plugins", "package-metadata")
-        await fs.mkdir(plugin, { recursive: true })
-        await fs.writeFile(path.join(plugin, "package.json"), JSON.stringify({ exports: "./entry.ts" }))
-        await fs.writeFile(path.join(plugin, "entry.ts"), discoveredPlugin("package-metadata"))
-      },
-    ),
-  )
-
-  it.live("loads auto-discovered plugin packages from index fallback", () =>
-    withLocation(
-      undefined,
-      Effect.gen(function* () {
-        yield* ready()
-        const plugins = yield* Plugin.Service
-        expect((yield* plugins.list()).map((plugin) => String(plugin.id))).toContain("index-fallback")
-      }),
-      false,
-      async (directory) => {
-        const plugin = path.join(directory, ".opencode", "plugins", "index-fallback")
-        await fs.mkdir(plugin, { recursive: true })
-        await fs.writeFile(path.join(plugin, "index.js"), discoveredPlugin("index-fallback"))
-      },
-    ),
-  )
-
-  it.live("prefers package metadata over index fallback", () =>
-    withLocation(
-      undefined,
-      Effect.gen(function* () {
-        yield* ready()
-        const plugins = yield* Plugin.Service
-        const ids = (yield* plugins.list()).map((plugin) => String(plugin.id))
-        expect(ids).toContain("metadata-precedence")
-        expect(ids).not.toContain("module-collision")
-        expect(ids).not.toContain("main-collision")
-        expect(ids).not.toContain("index-collision")
-      }),
-      false,
-      async (directory) => {
-        const plugin = path.join(directory, ".opencode", "plugins", "collision")
-        await fs.mkdir(plugin, { recursive: true })
-        await fs.writeFile(
-          path.join(plugin, "package.json"),
-          JSON.stringify({ exports: "./entry.js", module: "./module.js", main: "./main.js" }),
-        )
-        await fs.writeFile(path.join(plugin, "entry.js"), discoveredPlugin("metadata-precedence"))
-        await fs.writeFile(path.join(plugin, "module.js"), discoveredPlugin("module-collision"))
-        await fs.writeFile(path.join(plugin, "main.js"), discoveredPlugin("main-collision"))
-        await fs.writeFile(path.join(plugin, "index.js"), discoveredPlugin("index-collision"))
-      },
-    ),
-  )
-
   staticIt.live("uses only internal and SDK plugins when the static source is wired", () =>
     Effect.gen(function* () {
       const sdk = yield* SdkPlugins.Service
@@ -452,7 +389,3 @@ export default Plugin.define({
 })
 `
 }
-
-function discoveredPlugin(id: string) {
-  return `export default { id: ${JSON.stringify(id)}, setup() {} }`
-}

packages/protocol/openapi.json

@@ -14300,9 +14300,15 @@
               "agent": {
                 "type": "string"
               },
+              "previous": {
+                "type": "string"
+              },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
               },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
+              },
               "version": {
                 "type": "string"
               }
@@ -14373,9 +14379,6 @@
               },
               "agent": {
                 "type": "string"
-              },
-              "previous": {
-                "type": "string"
               }
             },
             "required": ["sessionID", "agent"],
@@ -14444,9 +14447,6 @@
               },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
-              },
-              "previous": {
-                "$ref": "#/components/schemas/Model.Ref"
               }
             },
             "required": ["sessionID", "model"],

packages/www/openapi.json

@@ -14300,9 +14300,15 @@
               "agent": {
                 "type": "string"
               },
+              "previous": {
+                "type": "string"
+              },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
               },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
+              },
               "version": {
                 "type": "string"
               }
@@ -14373,9 +14379,6 @@
               },
               "agent": {
                 "type": "string"
-              },
-              "previous": {
-                "type": "string"
               }
             },
             "required": ["sessionID", "agent"],
@@ -14444,9 +14447,6 @@
               },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
-              },
-              "previous": {
-                "$ref": "#/components/schemas/Model.Ref"
               }
             },
             "required": ["sessionID", "model"],

packages/www/public/openapi.json

@@ -14300,9 +14300,15 @@
               "agent": {
                 "type": "string"
               },
+              "previous": {
+                "type": "string"
+              },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
               },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
+              },
               "version": {
                 "type": "string"
               }
@@ -14373,9 +14379,6 @@
               },
               "agent": {
                 "type": "string"
-              },
-              "previous": {
-                "type": "string"
               }
             },
             "required": ["sessionID", "agent"],
@@ -14444,9 +14447,6 @@
               },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
-              },
-              "previous": {
-                "$ref": "#/components/schemas/Model.Ref"
               }
             },
             "required": ["sessionID", "model"],