feat(core): add session rename tool

packages/core/src/plugin/internal.ts

@@ -43,6 +43,7 @@ import { QuestionTool } from "../tool/plugin/question"
 import { ReadToolFileSystem } from "../tool/read-filesystem"
 import { ReadTool } from "../tool/plugin/read"
 import { ShellTool } from "../tool/plugin/shell"
+import { SessionRenameTool } from "../tool/plugin/session-rename"
 import { SkillTool } from "../tool/plugin/skill"
 import { SubagentTool } from "../tool/plugin/subagent"
 import { Tool } from "../tool"
@@ -149,6 +150,7 @@ const pre = [
   QuestionTool.Plugin,
   ReadTool.Plugin,
   ShellTool.Plugin,
+  SessionRenameTool.Plugin,
   SkillTool.Plugin,
   SubagentTool.Plugin,
   WebFetchTool.Plugin,

packages/core/src/tool/plugin/session-rename.ts

@@ -0,0 +1,77 @@
+export * as SessionRenameTool from "./session-rename"
+
+import type { Context as PluginContext } from "@opencode-ai/plugin/effect/plugin"
+import { ToolFailure } from "@opencode-ai/ai"
+import { Effect, Schema } from "effect"
+import { Permission } from "../../permission"
+import { PluginRuntime } from "../../plugin/runtime"
+
+export const name = "sessionRename"
+
+export const description =
+  "Rename the current session. Use a short, specific title that summarizes the work being done. This tool can only rename the session you are currently working in."
+
+export const Input = Schema.Struct({
+  title: Schema.String.check(
+    Schema.isMinLength(1, { message: "Title must not be empty" }),
+    Schema.isMaxLength(100, { message: "Title must be 100 characters or fewer" }),
+  ).annotate({ description: "New title for the current session" }),
+})
+
+export const Output = Schema.Struct({
+  title: Schema.String,
+})
+
+export const Plugin = {
+  id: "opencode.tool.session-rename",
+  effect: Effect.fn("SessionRenameTool.Plugin")(function* (ctx: PluginContext) {
+    const runtime = yield* PluginRuntime.Service
+    const permission = yield* Permission.Service
+
+    yield* ctx.tool
+      .transform((draft) =>
+        draft.add(
+          ({
+            name,
+            options: { codemode: false },
+            description,
+            input: Input,
+            output: Output,
+            execute: (input, context) =>
+              Effect.gen(function* () {
+                const title = input.title.replace(/\s+/g, " ").trim()
+                if (!title) return yield* new ToolFailure({ message: "Session title must not be empty" })
+                yield* permission
+                  .assert({
+                    action: name,
+                    resources: ["*"],
+                    save: ["*"],
+                    metadata: { title },
+                    sessionID: context.sessionID,
+                    agent: context.agent,
+                    source: { type: "tool", messageID: context.messageID, callID: context.callID },
+                  })
+                  .pipe(
+                    Effect.mapError(
+                      (error) => new ToolFailure({ message: "Permission denied: sessionRename", error }),
+                    ),
+                  )
+                yield* runtime.session
+                  .rename({ sessionID: context.sessionID, title })
+                  .pipe(
+                    Effect.mapError(
+                      (error) => new ToolFailure({ message: "Unable to rename the current session", error }),
+                    ),
+                  )
+                return {
+                  output: { title },
+                  content: `Renamed the current session to: ${title}`,
+                  metadata: { title },
+                }
+              }),
+          }),
+        ),
+      )
+      .pipe(Effect.orDie)
+  }),
+}