fix(core): keep nested MCP code mode tools direct

Co-authored-by: Aiden Cline <rekram1-node@users.noreply.github.com>

packages/app/src/components/prompt-input/submit.test.ts

@@ -534,14 +534,11 @@ describe("prompt submit worktree selection", () => {
         id: expect.stringMatching(/^msg_/),
         command: "review",
         arguments: "staged changes",
+        agent: "agent",
+        model: { id: "model", providerID: "provider", variant: "high" },
         files: [],
       },
     ])
-    expect(switchedAgents).toEqual([{ sessionID: "session-1", agent: "agent" }])
-    expect(switchedModels).toEqual([
-      { sessionID: "session-1", model: { id: "model", providerID: "provider", variant: "high" } },
-    ])
-    expect(sessionRequestOrder).toEqual(["agent", "model"])
     expect(serverSessionSyncs).toBe(0)
   })
 

packages/app/src/components/prompt-input/submit.ts

@@ -61,39 +61,23 @@ export async function sendFollowupDraft(input: FollowupSendInput) {
     input.serverSync.session.set("session_status", input.draft.sessionID, { type: "idle" })
   }
 
-  const select = async () => {
-    const session = input.session()
-    if (session?.agent !== input.draft.agent) {
-      await input.api.switchAgent({ sessionID: input.draft.sessionID, agent: input.draft.agent })
-    }
-    if (
-      session?.model?.providerID === input.draft.model.providerID &&
-      session.model.id === input.draft.model.modelID &&
-      (session.model.variant ?? "default") === (input.draft.variant ?? "default")
-    )
-      return
-    await input.api.switchModel({
-      sessionID: input.draft.sessionID,
-      model: {
-        id: input.draft.model.modelID,
-        providerID: input.draft.model.providerID,
-        variant: input.draft.variant,
-      },
-    })
-  }
-
   const [head, ...tail] = text.split(" ")
   const cmd = head?.startsWith("/") ? head.slice(1) : undefined
   if (cmd && input.sync.data.command.find((item) => item.name === cmd)) {
     setBusy()
     try {
-      await select()
       const messageID = Identifier.ascending("message")
       await input.api.command({
         sessionID: input.draft.sessionID,
         id: messageID,
         command: cmd,
         arguments: tail.join(" "),
+        agent: input.draft.agent,
+        model: {
+          id: input.draft.model.modelID,
+          providerID: input.draft.model.providerID,
+          variant: input.draft.variant,
+        },
         files: await Promise.all(
           images.map(async (attachment) => ({
             uri: await blobDataUrl(attachment.blob, attachment.mime),
@@ -134,7 +118,24 @@ export async function sendFollowupDraft(input: FollowupSendInput) {
   })
 
   try {
-    await select()
+    const session = input.session()
+    if (session?.agent !== input.draft.agent) {
+      await input.api.switchAgent({ sessionID: input.draft.sessionID, agent: input.draft.agent })
+    }
+    if (
+      session?.model?.providerID !== input.draft.model.providerID ||
+      session.model.id !== input.draft.model.modelID ||
+      (session.model.variant ?? "default") !== (input.draft.variant ?? "default")
+    ) {
+      await input.api.switchModel({
+        sessionID: input.draft.sessionID,
+        model: {
+          id: input.draft.model.modelID,
+          providerID: input.draft.model.providerID,
+          variant: input.draft.variant,
+        },
+      })
+    }
 
     const admitted = await input.api.prompt({
       sessionID: input.draft.sessionID,
@@ -468,23 +469,14 @@ export function createPromptSubmit(input: PromptSubmitInput) {
           clearInput()
           const messageID = Identifier.ascending("message")
           submissionServerSync.session.set("session_status", session.id, { type: "busy" })
-          void (async () => {
-            if (session.agent !== agent)
-              await submissionSDK.api.session.switchAgent({ sessionID: session.id, agent })
-            if (
-              session.model?.providerID !== model.providerID ||
-              session.model.id !== model.modelID ||
-              (session.model.variant ?? "default") !== (variant ?? "default")
-            )
-              await submissionSDK.api.session.switchModel({
-                sessionID: session.id,
-                model: { id: model.modelID, providerID: model.providerID, variant },
-              })
-            await submissionSDK.api.session.command({
+          void submissionSDK.api.session
+            .command({
               sessionID: session.id,
               id: messageID,
               command: commandName,
               arguments: args.join(" "),
+              agent,
+              model: { id: model.modelID, providerID: model.providerID, variant },
               files: await Promise.all(
                 images.map(async (attachment) => ({
                   uri: await blobDataUrl(attachment.blob, attachment.mime),
@@ -492,14 +484,14 @@ export function createPromptSubmit(input: PromptSubmitInput) {
                 })),
               ),
             })
-          })().catch((err) => {
-            submissionServerSync.session.set("session_status", session.id, { type: "idle" })
-            showToast({
-              title: language.t("prompt.toast.commandSendFailed.title"),
-              description: formatServerError(err, language.t, language.t("common.requestFailed")),
+            .catch((err) => {
+              submissionServerSync.session.set("session_status", session.id, { type: "idle" })
+              showToast({
+                title: language.t("prompt.toast.commandSendFailed.title"),
+                description: formatServerError(err, language.t, language.t("common.requestFailed")),
+              })
+              restoreInput()
             })
-            restoreInput()
-          })
           return
         }
       }

packages/client/src/effect/api/api.ts

@@ -192,6 +192,8 @@ export type Endpoint5_13Input = {
   readonly id?: SessionMessage.ID | undefined
   readonly command: string
   readonly arguments?: string | undefined
+  readonly agent?: Agent.ID | undefined
+  readonly model?: Model.Ref | undefined
   readonly files?: ReadonlyArray<PromptInput.FileAttachment> | undefined
   readonly agents?: ReadonlyArray<AgentAttachment> | undefined
   readonly skills?: ReadonlyArray<PromptInput.SkillAttachment> | undefined

packages/client/src/effect/generated/client.ts

@@ -423,6 +423,8 @@ const Endpoint5_13 = (raw: RawClient["server.session"]) => (input: Endpoint5_13I
         id: input["id"],
         command: input["command"],
         arguments: input["arguments"],
+        agent: input["agent"],
+        model: input["model"],
         files: input["files"],
         agents: input["agents"],
         skills: input["skills"],

packages/client/src/promise/generated/client.ts

@@ -627,6 +627,8 @@ export function make(options: ClientOptions) {
               id: input["id"],
               command: input["command"],
               arguments: input["arguments"],
+              agent: input["agent"],
+              model: input["model"],
               files: input["files"],
               agents: input["agents"],
               skills: input["skills"],

packages/client/src/promise/generated/types.ts

@@ -3511,6 +3511,8 @@ export type SessionCommandInput = {
     readonly id?: string | null
     readonly command: string
     readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
     readonly files?: ReadonlyArray<{
       readonly uri: string
       readonly name?: string
@@ -3532,6 +3534,8 @@ export type SessionCommandInput = {
     readonly id?: string | null
     readonly command: string
     readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
     readonly files?: ReadonlyArray<{
       readonly uri: string
       readonly name?: string
@@ -3553,6 +3557,8 @@ export type SessionCommandInput = {
     readonly id?: string | null
     readonly command: string
     readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
     readonly files?: ReadonlyArray<{
       readonly uri: string
       readonly name?: string
@@ -3570,10 +3576,58 @@ export type SessionCommandInput = {
     readonly delivery?: ("steer" | "queue") | null
     readonly resume?: boolean | null
   }["arguments"]
+  readonly agent?: {
+    readonly id?: string | null
+    readonly command: string
+    readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
+    readonly files?: ReadonlyArray<{
+      readonly uri: string
+      readonly name?: string
+      readonly description?: string
+      readonly mention?: { readonly start: number; readonly end: number; readonly text: string }
+    }>
+    readonly agents?: ReadonlyArray<{
+      readonly name: string
+      readonly mention?: { readonly start: number; readonly end: number; readonly text: string }
+    }>
+    readonly skills?: ReadonlyArray<{
+      readonly id: string
+      readonly mention?: { readonly start: number; readonly end: number; readonly text: string }
+    }>
+    readonly delivery?: ("steer" | "queue") | null
+    readonly resume?: boolean | null
+  }["agent"]
+  readonly model?: {
+    readonly id?: string | null
+    readonly command: string
+    readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
+    readonly files?: ReadonlyArray<{
+      readonly uri: string
+      readonly name?: string
+      readonly description?: string
+      readonly mention?: { readonly start: number; readonly end: number; readonly text: string }
+    }>
+    readonly agents?: ReadonlyArray<{
+      readonly name: string
+      readonly mention?: { readonly start: number; readonly end: number; readonly text: string }
+    }>
+    readonly skills?: ReadonlyArray<{
+      readonly id: string
+      readonly mention?: { readonly start: number; readonly end: number; readonly text: string }
+    }>
+    readonly delivery?: ("steer" | "queue") | null
+    readonly resume?: boolean | null
+  }["model"]
   readonly files?: {
     readonly id?: string | null
     readonly command: string
     readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
     readonly files?: ReadonlyArray<{
       readonly uri: string
       readonly name?: string
@@ -3595,6 +3649,8 @@ export type SessionCommandInput = {
     readonly id?: string | null
     readonly command: string
     readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
     readonly files?: ReadonlyArray<{
       readonly uri: string
       readonly name?: string
@@ -3616,6 +3672,8 @@ export type SessionCommandInput = {
     readonly id?: string | null
     readonly command: string
     readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
     readonly files?: ReadonlyArray<{
       readonly uri: string
       readonly name?: string
@@ -3637,6 +3695,8 @@ export type SessionCommandInput = {
     readonly id?: string | null
     readonly command: string
     readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
     readonly files?: ReadonlyArray<{
       readonly uri: string
       readonly name?: string
@@ -3658,6 +3718,8 @@ export type SessionCommandInput = {
     readonly id?: string | null
     readonly command: string
     readonly arguments?: string | null
+    readonly agent?: string | null
+    readonly model?: { readonly id: string; readonly providerID: string; readonly variant?: string } | null
     readonly files?: ReadonlyArray<{
       readonly uri: string
       readonly name?: string

packages/core/src/plugin/internal.ts

@@ -63,6 +63,7 @@ import { AgentPlugin } from "./agent.js"
 import { CommandPlugin } from "./command.js"
 import { PlanPlugin } from "./plan.js"
 import { ModelsDevPlugin } from "./models-dev.js"
+import { McpCodeModePlugin } from "./mcp-codemode.js"
 import { ProviderPlugins } from "./provider.js"
 import { WebSearchPlugins } from "./websearch/index.js"
 import { PluginRuntime } from "./runtime.js"
@@ -94,6 +95,7 @@ const services = Effect.fn("PluginInternal.services")(function* () {
   const location = yield* Location.Service
   const locationMutation = yield* LocationMutation.Service
   const models = yield* ModelsDev.Service
+  const mcpCodeMode = yield* McpCodeModePlugin.Service
   const npm = yield* Npm.Service
   const permission = yield* Permission.Service
   const runtime = yield* PluginRuntime.Service
@@ -131,6 +133,7 @@ const services = Effect.fn("PluginInternal.services")(function* () {
     Context.make(Location.Service, location),
     Context.make(LocationMutation.Service, locationMutation),
     Context.make(ModelsDev.Service, models),
+    Context.make(McpCodeModePlugin.Service, mcpCodeMode),
     Context.make(Npm.Service, npm),
     Context.make(Permission.Service, permission),
     Context.make(PluginRuntime.Service, runtime),
@@ -175,6 +178,7 @@ export const requirements = LayerNode.group([
   Location.node,
   LocationMutation.node,
   ModelsDev.node,
+  McpCodeModePlugin.node,
   Npm.node,
   Permission.node,
   PluginRuntime.node,
@@ -202,6 +206,7 @@ const pre = [
   SkillPlugin.Plugin,
   ...SystemPromptPlugin.Plugins,
   ModelsDevPlugin,
+  McpCodeModePlugin.Plugin,
   ...ProviderPlugins,
   ...WebSearchPlugins,
   PatchTool.Plugin,

packages/core/src/plugin/mcp-codemode.ts

@@ -0,0 +1,51 @@
+export * as McpCodeModePlugin from "./mcp-codemode.js"
+
+import { define } from "@opencode-ai/plugin/effect/plugin"
+import { ConfigMCP } from "@opencode-ai/schema/config/mcp"
+import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
+import { Context, Effect, Layer, Scope } from "effect"
+
+const directToolHosts = new Set(["mcp.cloudflare.com"])
+type Resolver = (config: typeof ConfigMCP.Server.Type) => boolean | undefined
+
+export interface Interface {
+  register: (resolver: Resolver) => Effect.Effect<void, never, Scope.Scope>
+  resolve: (config: typeof ConfigMCP.Server.Type) => boolean | undefined
+}
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/McpCodeModePlugin") {}
+
+export const layer = Layer.effect(
+  Service,
+  Effect.sync(() => {
+    let resolvers: Resolver[] = []
+    return Service.of({
+      register: Effect.fn("McpCodeModePlugin.register")(function* (resolver) {
+        resolvers = [...resolvers, resolver]
+        yield* Effect.addFinalizer(() => Effect.sync(() => (resolvers = resolvers.filter((item) => item !== resolver))))
+      }),
+      resolve: (config) =>
+        resolvers
+          .toReversed()
+          .map((resolver) => resolver(config))
+          .find((value) => value !== undefined),
+    })
+  }),
+)
+
+export const node = makeLocationNode({ service: Service, layer, deps: [] })
+
+export const Plugin = define({
+  id: "opencode.mcp.codemode-compatibility",
+  effect: Effect.fn(function* () {
+    const defaults = yield* Service
+    yield* defaults.register(codeModeCompatibilityDefault)
+  }),
+})
+
+export function codeModeCompatibilityDefault(config: typeof ConfigMCP.Server.Type) {
+  if (config.type !== "remote") return
+  const url = URL.parse(config.url)
+  if (!url || !directToolHosts.has(url.hostname.toLowerCase())) return
+  return false
+}

packages/core/src/session.ts

@@ -233,6 +233,8 @@ export interface Interface {
     sessionID: SessionSchema.ID
     command: string
     arguments?: string
+    agent?: Agent.ID
+    model?: Model.Ref
     files?: PromptInput.Prompt["files"]
     agents?: PromptInput.Prompt["agents"]
     skills?: PromptInput.Prompt["skills"]
@@ -619,13 +621,13 @@ const layer = Layer.effect(
         const evaluated = yield* commands.evaluate({ name: input.command, arguments: input.arguments })
 
         // TODO(v2 commands): decide whether command-level subtask/background execution belongs in v2 commands.
-        const agent = command.agent
+        const agent = command.agent ?? input.agent
         const commandAgent = yield* Effect.gen(function* () {
           if (!command.agent) return undefined
           const agents = yield* Agent.Service.pipe(Effect.provide(locations.get(session.location)))
           return yield* agents.get(Agent.ID.make(command.agent))
         })
-        const model = command.model ?? commandAgent?.model
+        const model = command.model ?? commandAgent?.model ?? input.model
         if (agent !== undefined && session.agent !== Agent.ID.make(agent))
           yield* result.switchAgent({ sessionID: input.sessionID, agent: Agent.ID.make(agent) })
         if (model !== undefined) yield* result.switchModel({ sessionID: input.sessionID, model })

packages/core/src/session/generate-node.ts

@@ -11,6 +11,7 @@ import { SessionContext } from "./context.js"
 import { SessionGenerate } from "./generate.js"
 import { SessionHistory } from "./history.js"
 import { SessionModelHeaders } from "./model-headers.js"
+import { SessionModelHttp } from "./model-http.js"
 import { SessionPromptCacheKey } from "./prompt-cache-key.js"
 import { SessionRunnerModel } from "./runner/model.js"
 import { SessionSystemPrompt } from "./system-prompt.js"
@@ -79,6 +80,13 @@ export const layer = Layer.effect(
             messages: contextEvent.messages,
             tools: hookedTools,
           }),
+          {
+            http: SessionModelHttp.middleware(hooks, {
+              sessionID: selection.session.id,
+              agent: selection.agent.id,
+              model: model.ref,
+            }),
+          },
         )
         yield* Effect.logInfo("session generation usage diagnostic", { usage: response.usage })
         return response.text

packages/core/src/tool/mcp.ts

@@ -2,12 +2,17 @@ export * as McpTool from "./mcp.js"
 
 import { ToolFailure } from "@opencode-ai/ai"
 import { McpEvent } from "@opencode-ai/schema/mcp-event"
+import { Document } from "@opencode-ai/schema/config"
 import { Context, Effect, Exit, Fiber, type JsonSchema, Layer, Scope, Semaphore, Stream } from "effect"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import { Bus } from "../bus.js"
 
 import { MCP } from "../mcp/index.js"
+import { Config } from "../config.js"
 import { Permission } from "../permission.js"
+import { Plugin } from "../plugin.js"
+import { McpCodeModePlugin } from "../plugin/mcp-codemode.js"
+import { PluginSupervisor } from "../plugin/supervisor.js"
 import { Tool } from "../tool.js"
 
 /**
@@ -27,6 +32,8 @@ export const layer = Layer.effect(
   Service,
   Effect.gen(function* () {
     const mcp = yield* MCP.Service
+    const config = yield* Config.Service
+    const codemode = yield* McpCodeModePlugin.Service
     const tools = yield* Tool.Service
     const bus = yield* Bus.Service
     const permission = yield* Permission.Service
@@ -39,14 +46,23 @@ export const layer = Layer.effect(
     const reconcile = lock.withPermit(
       Effect.gen(function* () {
         const discovered = yield* mcp.tools()
+        const servers = new Map(
+          (yield* config.entries())
+            .filter((entry): entry is Document => entry.type === "document")
+            .flatMap((entry) => Object.entries(entry.info.mcp?.servers ?? {})),
+        )
         const next = yield* Scope.fork(scope)
         yield* tools
           .transform((draft) => {
             for (const tool of discovered) {
               const schema = (tool.inputSchema ?? {}) as JsonSchema.JsonSchema
+              const server = servers.get(tool.server)
               draft.add({
                 name: tool.name,
-                options: { namespace: namespace(tool.server), codemode: tool.codemode !== false },
+                options: {
+                  namespace: namespace(tool.server),
+                  codemode: (tool.codemode ?? (server ? codemode.resolve(server) : undefined)) !== false,
+                },
                 description: tool.description ?? "",
                 input: {
                   ...schema,
@@ -122,7 +138,7 @@ export const layer = Layer.effect(
     )
 
     const initial = yield* reconcile.pipe(Effect.forkScoped)
-    yield* bus.subscribe(McpEvent.ToolsChanged).pipe(
+    yield* bus.subscribe([McpEvent.ToolsChanged, Plugin.Event.Updated]).pipe(
       Stream.runForEach(() => reconcile),
       Effect.forkScoped({ startImmediately: true }),
     )
@@ -133,5 +149,5 @@ export const layer = Layer.effect(
 export const node = makeLocationNode({
   service: Service,
   layer,
-  deps: [Tool.node, MCP.node, Bus.node, Permission.node],
+  deps: [Tool.node, MCP.node, McpCodeModePlugin.node, Config.node, Bus.node, Permission.node, PluginSupervisor.node],
 })

packages/core/test/mcp.test.ts

@@ -29,6 +29,8 @@ import { MCP } from "@opencode-ai/core/mcp/index"
 import { MCPClient } from "@opencode-ai/core/mcp/client"
 import { MCPStdio } from "@opencode-ai/core/mcp/stdio"
 import { Permission } from "@opencode-ai/core/permission"
+import { McpCodeModePlugin } from "@opencode-ai/core/plugin/mcp-codemode"
+import { PluginSupervisor } from "@opencode-ai/core/plugin/supervisor"
 import { AbsolutePath } from "@opencode-ai/core/schema"
 import { Session } from "@opencode-ai/core/session"
 import { McpTool } from "@opencode-ai/core/tool/mcp"
@@ -336,12 +338,16 @@ const permissions = Layer.mock(Permission.Service, {
     }),
 })
 const events = Layer.mock(Bus.Service, { subscribe: () => Stream.never })
+const plugins = Layer.succeed(PluginSupervisor.Service, PluginSupervisor.Service.of({ flush: Effect.void }))
 const it = testEffect(
   AppNodeBuilder.build(LayerNode.group([Tool.node, McpTool.node]), [
     [MCP.node, mcp],
+    [McpCodeModePlugin.node, McpCodeModePlugin.layer],
+    [Config.node, Config.testLayer()],
     [Permission.node, permissions],
     [Bus.node, events],
     [Image.node, imagePassthrough],
+    [PluginSupervisor.node, plugins],
   ]),
 )
 

packages/core/test/plugin/mcp-codemode.test.ts

@@ -0,0 +1,36 @@
+import { ConfigMCP } from "@opencode-ai/schema/config/mcp"
+import { codeModeCompatibilityDefault, McpCodeModePlugin } from "@opencode-ai/core/plugin/mcp-codemode"
+import { describe, expect, it } from "bun:test"
+import { Effect } from "effect"
+
+describe("MCP Code Mode compatibility defaults", () => {
+  it("keeps Cloudflare's Code Mode MCP server direct by default", () => {
+    const config = new ConfigMCP.Remote({ type: "remote", url: "https://mcp.cloudflare.com/mcp" })
+    expect(codeModeCompatibilityDefault(config)).toBe(false)
+  })
+
+  it("does not change Cloudflare's product-specific MCP servers", () => {
+    const config = new ConfigMCP.Remote({ type: "remote", url: "https://docs.mcp.cloudflare.com/mcp" })
+    expect(codeModeCompatibilityDefault(config)).toBeUndefined()
+  })
+
+  it("does not change local or unrelated remote servers", () => {
+    const local = new ConfigMCP.Local({ type: "local", command: ["server"] })
+    const remote = new ConfigMCP.Remote({ type: "remote", url: "https://example.com/mcp" })
+    expect(codeModeCompatibilityDefault(local)).toBeUndefined()
+    expect(codeModeCompatibilityDefault(remote)).toBeUndefined()
+  })
+
+  it("retains a registered direct-tool default", async () => {
+    await Effect.runPromise(
+      Effect.scoped(
+        Effect.gen(function* () {
+          const defaults = yield* McpCodeModePlugin.Service
+          yield* defaults.register(codeModeCompatibilityDefault)
+          const config = new ConfigMCP.Remote({ type: "remote", url: "https://mcp.cloudflare.com/mcp" })
+          expect(defaults.resolve(config)).toBe(false)
+        }).pipe(Effect.provide(McpCodeModePlugin.layer)),
+      ),
+    )
+  })
+})

packages/core/test/session-generate.test.ts

@@ -51,15 +51,17 @@ import { Effect, Layer, Schema, Stream } from "effect"
 import { testEffect } from "./lib/effect"
 
 const requests: LLMRequest[] = []
+let hasHttpMiddleware = false
 let instruction: string | Instructions.Unavailable = "Initial context"
 const sessionID = SessionSchema.ID.make("ses_generate_test")
 
 const model = LanguageModel.make({ id: "generate-model", provider: "test", route: OpenAIChat.route })
 const client = Layer.mock(LLMClient.Service)({
   stream: () => Stream.die(new Error("unused")),
-  generate: (request) =>
+  generate: (request, options) =>
     Effect.sync(() => {
       requests.push(request)
+      hasHttpMiddleware = typeof options?.http === "function"
       const response = LLMResponse.fromEvents([
         LLMEvent.stepStart({ index: 0 }),
         LLMEvent.textStart({ id: "generate" }),
@@ -221,6 +223,7 @@ const setup = Effect.gen(function* () {
 it.effect("generates from fresh settled Session context without durable mutation", () =>
   Effect.gen(function* () {
     requests.length = 0
+    hasHttpMiddleware = false
     instruction = "Initial context"
     const { db, bus, instructions } = yield* setup
     yield* InstructionState.prepare(db, bus, instructions, sessionID)
@@ -298,6 +301,7 @@ it.effect("generates from fresh settled Session context without durable mutation
 
     expect(result).toBe("Transient answer")
     expect(requests).toHaveLength(1)
+    expect(hasHttpMiddleware).toBe(true)
     expect(requests[0]?.model).toBe(model)
     expect(requests[0]?.system[0]?.text).toBe("Hooked system")
     expect(requests[0]?.system.map((part) => part.text)).toContain("Initial context")

packages/protocol/src/groups/session.ts

@@ -341,6 +341,8 @@ export const makeSessionGroup = <I extends HttpApiMiddleware.AnyId, S>(sessionLo
           id: SessionMessage.ID.pipe(Schema.optional),
           command: Schema.String,
           arguments: Schema.String.pipe(Schema.optional),
+          agent: Agent.ID.pipe(Schema.optional),
+          model: Model.Ref.pipe(Schema.optional),
           files: PromptInput.Prompt.fields.files,
           agents: PromptInput.Prompt.fields.agents,
           skills: PromptInput.Prompt.fields.skills,

packages/server/src/handlers/session.ts

@@ -356,6 +356,8 @@ export const SessionHandler = HttpApiBuilder.group(Api, "server.session", (handl
                 id: ctx.payload.id,
                 command: ctx.payload.command,
                 arguments: ctx.payload.arguments,
+                agent: ctx.payload.agent,
+                model: ctx.payload.model,
                 files: ctx.payload.files,
                 agents: ctx.payload.agents,
                 skills: ctx.payload.skills,

packages/session-ui/src/components/message-part.tsx

@@ -547,6 +547,12 @@ export function getToolInfo(
         title: i18n.t("ui.tool.shell"),
         subtitle: input.command,
       }
+    case "execute":
+      return {
+        icon: "console",
+        title: i18n.t("ui.tool.execute"),
+        subtitle: input.code,
+      }
     case "edit":
       return {
         icon: "code-lines",
@@ -1574,6 +1580,7 @@ PART_MAPPING["tool"] = function ToolPartDisplay(props) {
     if (typeof value === "string" && value) return value
     return taskId()
   })
+  const toolError = createMemo(() => partError(part(), i18n.t("ui.toolErrorCard.failed")))
 
   const render = createMemo(() => ToolRegistry.render(part().tool) ?? GenericTool)
   const controlledOpen = () => (props.onToolOpenChange ? (props.toolOpen ?? props.defaultOpen) : undefined)
@@ -1583,7 +1590,7 @@ PART_MAPPING["tool"] = function ToolPartDisplay(props) {
     <Show when={!hideQuestion()}>
       <div data-component="tool-part-wrapper" data-timeline-part-id={part().id}>
         <Switch>
-          <Match when={part().state.status === "error" && (part().state as any).error}>
+          <Match when={toolError()}>
             {(error) => {
               const cleaned = error().replace("Error: ", "")
               if (part().tool === "question" && cleaned.includes("dismissed this question")) {
@@ -1644,6 +1651,26 @@ PART_MAPPING["tool"] = function ToolPartDisplay(props) {
   )
 }
 
+function partError(part: ToolPart, fallback: string) {
+  if (part.state.status === "error") return part.state.error
+  if (part.tool !== "execute" || !("metadata" in part.state)) return undefined
+  const calls = part.state.metadata?.toolCalls
+  const failed =
+    part.state.metadata?.error === true ||
+    (Array.isArray(calls) &&
+      calls.some(
+        (call) =>
+          call !== null &&
+          typeof call === "object" &&
+          !Array.isArray(call) &&
+          "status" in call &&
+          call.status === "error",
+      ))
+  if (!failed) return undefined
+  if ("output" in part.state && typeof part.state.output === "string" && part.state.output) return part.state.output
+  return fallback
+}
+
 export function MessageDivider(props: { label: string }) {
   return (
     <div data-component="compaction-part">
@@ -2104,6 +2131,84 @@ ToolRegistry.register({
 
 ToolRegistry.register({ name: "subagent", render: ToolRegistry.render("task") })
 
+function ConsoleOutput(props: { copy: string; children: JSX.Element }) {
+  const i18n = useI18n()
+  const [copied, setCopied] = createSignal(false)
+
+  const copy = async () => {
+    if (!props.copy) return
+    if (!(await writeClipboard(props.copy))) return
+    setCopied(true)
+    setTimeout(() => setCopied(false), 2000)
+  }
+
+  return (
+    <div data-component="bash-output" dir="ltr">
+      <div data-slot="bash-copy">
+        <TooltipV2 value={copied() ? i18n.t("ui.message.copied") : i18n.t("ui.message.copy")} placement="top">
+          <IconButtonV2
+            icon={<IconV2 name={copied() ? "check" : "outline-copy"} size="small" />}
+            size="normal"
+            variant="ghost-muted"
+            onMouseDown={(event) => event.preventDefault()}
+            onClick={copy}
+            aria-label={copied() ? i18n.t("ui.message.copied") : i18n.t("ui.message.copy")}
+          />
+        </TooltipV2>
+      </div>
+      <div
+        data-slot="bash-scroll"
+        data-scrollable
+        tabIndex={0}
+        role="region"
+        aria-label={i18n.t("ui.scrollView.ariaLabel")}
+      >
+        <pre data-slot="bash-pre">
+          <code>{props.children}</code>
+        </pre>
+      </div>
+    </div>
+  )
+}
+
+ToolRegistry.register({
+  name: "execute",
+  render(props) {
+    const i18n = useI18n()
+    const pending = () => props.status === "pending" || props.status === "streaming" || props.status === "running"
+    const code = createMemo(() => (typeof props.input.code === "string" ? props.input.code : ""))
+    const text = createMemo(() => {
+      const output = stripAnsi(props.output ?? "").replace(/\r\n?/g, "\n")
+      return `${code()}${output ? "\n\n" + output : ""}`
+    })
+    const sawPending = pending()
+    return (
+      <BasicTool
+        {...props}
+        icon="console"
+        allowOpenWhilePending
+        trigger={(open) => (
+          <div data-slot="basic-tool-tool-info-structured">
+            <span data-slot="basic-tool-tool-indicator">
+              <Icon name="console" size="small" />
+            </span>
+            <div data-slot="basic-tool-tool-info-main">
+              <span data-slot="basic-tool-tool-title">
+                <TextShimmer text={i18n.t("ui.tool.execute")} active={pending()} />
+              </span>
+              <Show when={!open() && code()}>
+                <ShellSubmessage text={code()} animate={sawPending} />
+              </Show>
+            </div>
+          </div>
+        )}
+      >
+        <ConsoleOutput copy={text()}>{text()}</ConsoleOutput>
+      </BasicTool>
+    )
+  },
+})
+
 ToolRegistry.register({
   name: "shell",
   render(props) {
@@ -2116,17 +2221,6 @@ ToolRegistry.register({
       const out = stripAnsi(props.output || props.metadata.output || "").replace(/\r\n?/g, "\n")
       return `${command()}${out ? "\n\n" + out : ""}`
     })
-    const [copied, setCopied] = createSignal(false)
-
-    const handleCopy = async () => {
-      const content = command()
-      if (!content) return
-      if (await writeClipboard(content)) {
-        setCopied(true)
-        setTimeout(() => setCopied(false), 2000)
-      }
-    }
-
     return (
       <BasicTool
         {...props}
@@ -2145,36 +2239,12 @@ ToolRegistry.register({
           </div>
         )}
       >
-        <div data-component="bash-output" dir="ltr">
-          <div data-slot="bash-copy">
-            <TooltipV2 value={copied() ? i18n.t("ui.message.copied") : i18n.t("ui.message.copy")} placement="top">
-              <IconButtonV2
-                icon={<IconV2 name={copied() ? "check" : "outline-copy"} size="small" />}
-                size="normal"
-                variant="ghost-muted"
-                onMouseDown={(e) => e.preventDefault()}
-                onClick={handleCopy}
-                aria-label={copied() ? i18n.t("ui.message.copied") : i18n.t("ui.message.copy")}
-              />
-            </TooltipV2>
-          </div>
-          <div
-            data-slot="bash-scroll"
-            data-scrollable
-            tabIndex={0}
-            role="region"
-            aria-label={i18n.t("ui.scrollView.ariaLabel")}
-          >
-            <pre data-slot="bash-pre">
-              <code>
-                <span data-slot="bash-prompt" aria-hidden="true">
-                  {"$ "}
-                </span>
-                {text()}
-              </code>
-            </pre>
-          </div>
-        </div>
+        <ConsoleOutput copy={command()}>
+          <span data-slot="bash-prompt" aria-hidden="true">
+            {"$ "}
+          </span>
+          {text()}
+        </ConsoleOutput>
       </BasicTool>
     )
   },

packages/session-ui/src/components/part-default-open.test.ts

@@ -71,8 +71,9 @@ describe("partDefaultOpen", () => {
     ).toBe(true)
   })
 
-  test("preserves shell defaults", () => {
+  test("applies shell defaults to console tools", () => {
     expect(partDefaultOpen(tool("shell", {}), true, false)).toBe(true)
+    expect(partDefaultOpen(tool("execute", {}), true, false)).toBe(true)
   })
 })
 

packages/session-ui/src/components/part-default-open.ts

@@ -23,7 +23,7 @@ function deletionOnly(part: ToolPart) {
 
 export function partDefaultOpen(part: PartType, shell = false, edit = false): boolean | undefined {
   if (part.type !== "tool") return undefined
-  if (part.tool === "bash" || part.tool === "shell") return shell
+  if (part.tool === "bash" || part.tool === "shell" || part.tool === "execute") return shell
   if (part.tool === "edit" || part.tool === "write" || part.tool === "patch" || part.tool === "apply_patch") {
     if (!edit) return false
     return !deletionOnly(part)

packages/session-ui/src/components/tool-error-card.tsx

@@ -54,6 +54,7 @@ export function ToolErrorCard(props: ToolErrorCardProps) {
       websearch: "ui.tool.websearch",
       bash: "ui.tool.shell",
       shell: "ui.tool.shell",
+      execute: "ui.tool.execute",
       patch: "ui.tool.patch",
       apply_patch: "ui.tool.patch",
       question: "ui.tool.questions",

packages/tui/src/component/prompt/index.tsx

@@ -1220,23 +1220,15 @@ export function Prompt(props: PromptProps) {
     } else if (slashHead && isCommand) {
       move.startSubmit()
       const model = { providerID: selection.providerID, id: selection.modelID, variant }
-      if (session?.agent !== agent.id) await client.api.session.switchAgent({ sessionID, agent: agent.id })
       const cancelCommit = local.model.trackSessionCommit(sessionID, model)
-      if (
-        session?.model?.providerID !== model.providerID ||
-        session.model.id !== model.id ||
-        (session.model.variant ?? "default") !== (model.variant ?? "default")
-      )
-        await client.api.session.switchModel({ sessionID, model }).catch((error) => {
-          cancelCommit()
-          throw error
-        })
 
       void client.api.session
         .command({
           sessionID,
           command: slashHead.name,
           arguments: slashHead.arguments,
+          agent: agent.id,
+          model,
           files: store.prompt.files,
           agents: store.prompt.agents,
           skills: store.prompt.skills?.length ? store.prompt.skills : undefined,

packages/tui/src/mini/stream-v2.transport.ts

@@ -1647,6 +1647,8 @@ export async function createSessionTransport(input: StreamInput): Promise<Sessio
       )
     }
 
+    const selected = await resolveSelectedModel(input, client, next)
+    if (next.variant && !selected) throw new Error("Cannot select a variant before selecting a model")
     input.trace?.write("send.command", { sessionID: input.sessionID, messageID, command: command.name, delivery })
     return client.session.command(
       {
@@ -1654,6 +1656,8 @@ export async function createSessionTransport(input: StreamInput): Promise<Sessio
         id: messageID,
         command: command.name,
         arguments: command.arguments,
+        agent: next.agent,
+        model: selected,
         files: attachments.files.length ? attachments.files : undefined,
         agents: agents.length ? agents : undefined,
         skills: skills.length ? skills : undefined,
@@ -1696,10 +1700,12 @@ export async function createSessionTransport(input: StreamInput): Promise<Sessio
       const client = sdk
       if (next.agent)
         await client.session.switchAgent({ sessionID: input.sessionID, agent: next.agent }, { signal: next.signal })
-      const selected = await resolveSelectedModel(input, client, next)
-      if (next.variant && !selected) throw new Error("Cannot select a variant before selecting a model")
-      if (selected)
-        await client.session.switchModel({ sessionID: input.sessionID, model: selected }, { signal: next.signal })
+      if (!next.prompt.command) {
+        const selected = await resolveSelectedModel(input, client, next)
+        if (next.variant && !selected) throw new Error("Cannot select a variant before selecting a model")
+        if (selected)
+          await client.session.switchModel({ sessionID: input.sessionID, model: selected }, { signal: next.signal })
+      }
       mergePending(await admitPrompt(next, client, delivery))
       settlementClient = client
     },
@@ -1738,12 +1744,6 @@ export async function createSessionTransport(input: StreamInput): Promise<Sessio
         return
       }
       if (command) {
-        if (next.agent)
-          await client.session.switchAgent({ sessionID: input.sessionID, agent: next.agent }, { signal: next.signal })
-        const selected = await resolveSelectedModel(input, client, next)
-        if (next.variant && !selected) throw new Error("Cannot select a variant before selecting a model")
-        if (selected)
-          await client.session.switchModel({ sessionID: input.sessionID, model: selected }, { signal: next.signal })
         await runTurnWait(
           next,
           messageID,

packages/tui/test/mini/stream-v2.transport.test.ts

@@ -2855,6 +2855,8 @@ describe("V2 mini transport", () => {
       id: "msg_cmd",
       command: "deploy",
       arguments: "prod",
+      agent: "build",
+      model: { providerID: "test", id: "model" },
       files: [
         { uri: "file:///tmp/context.txt", name: "context.txt" },
         {
@@ -2866,11 +2868,9 @@ describe("V2 mini transport", () => {
       skills: [{ id: "api-design", mention: { start: 13, end: 24, text: "/api-design" } }],
       delivery: "steer",
     })
-    expect(client.session.switchAgent).toHaveBeenCalledWith({ sessionID: "ses_1", agent: "build" }, expect.anything())
-    expect(client.session.switchModel).toHaveBeenCalledWith(
-      { sessionID: "ses_1", model: { providerID: "test", id: "model" } },
-      expect.anything(),
-    )
+    // Selection rides the command payload; no separate client-side switch.
+    expect(client.session.switchAgent).not.toHaveBeenCalled()
+    expect(client.session.switchModel).not.toHaveBeenCalled()
     await transport.close()
   })
 

packages/ui/src/i18n/en.ts

@@ -158,6 +158,7 @@ const source = {
   "ui.tool.websearch": "Web Search",
   "ui.tool.websearch.provider": "{{provider}} Web Search",
   "ui.tool.shell": "Shell",
+  "ui.tool.execute": "Execute",
   "ui.tool.patch": "Patch",
   "ui.tool.questions": "Questions",
   "ui.tool.questions.numbered": "Questions {{number}}",