feat: add dynamic tool loading for official models and per-server MCP deferred disclosure

.changeset/dynamic-tools-official-models.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Add the dynamically_loaded_tools capability to official Kimi Code models when the service declares support for message-level tool declarations.

.changeset/mcp-server-deferred-config.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Add a per-server `deferred` field to MCP server configuration: when the model supports dynamic tool loading (experimental `tool-select` flag), set `deferred: false` to keep a server's tools in the top-level tool list instead of loading them on demand via `select_tools`.

.changeset/select-tools-profile-activation.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Fix the select_tools tool never being registered because agent profiles do not list it in their tool allowlists.

docs/en/customization/mcp.md

@@ -62,6 +62,7 @@ Optional fields:
 | `headers` | `Record<string, string>` | HTTP, SSE | Static request headers appended to every request |
 | `bearerTokenEnvVar` | `string` | HTTP, SSE | Name of an environment variable that contains a bearer token |
 | `enabled` | `boolean` | All | Set to `false` to disable this server |
+| `deferred` | `boolean` | All | Experimental: with the `tool-select` flag and a model that declares dynamically loaded tools, this server's tools stay out of the top-level tool list and are loaded on demand via `select_tools`; set to `false` to always expose them inline. Defaults to `true`; ignored while the flag is off |
 | `startupTimeoutMs` | `number` | All | Connection timeout from `1` to `2147483647` milliseconds; default `30000` |
 | `toolTimeoutMs` | `number` | All | Timeout from `1` to `2147483647` milliseconds for a single tool call |
 | `enabledTools` | `string[]` | All | Tool allowlist |

docs/zh/customization/mcp.md

@@ -62,8 +62,9 @@ MCP server 配置写在 `mcp.json` 中，分两层：
 | `headers` | `Record<string, string>` | HTTP、SSE | 附加到每次请求的静态请求头 |
 | `bearerTokenEnvVar` | `string` | HTTP、SSE | 存放 bearer token 的环境变量名 |
 | `enabled` | `boolean` | 全部 | 设为 `false` 可禁用该 server |
-| `startupTimeoutMs` | `number` | 全部 | 连接超时，默认 `30000` 毫秒 |
-| `toolTimeoutMs` | `number` | 全部 | 单次工具调用超时（毫秒） |
+| `deferred` | `boolean` | 全部 | 实验功能：启用 `tool-select` 标志且模型声明动态工具加载能力时，该 server 的工具默认不进入顶层工具列表，由模型通过 `select_tools` 按需加载；设为 `false` 则始终直接暴露。默认 `true`；标志未启用时该字段无效 |
+| `startupTimeoutMs` | `number` | 全部 | 连接超时，取值范围为 `1` 到 `2147483647` 毫秒，默认 `30000` |
+| `toolTimeoutMs` | `number` | 全部 | 单次工具调用超时，取值范围为 `1` 到 `2147483647` 毫秒 |
 | `enabledTools` | `string[]` | 全部 | 工具白名单 |
 | `disabledTools` | `string[]` | 全部 | 工具黑名单 |
 

packages/agent-core-v2/src/agent/mcp/mcp.ts

@@ -11,6 +11,7 @@ export interface McpResolvedServer {
   readonly tools: readonly KosongTool[];
   readonly rawTools: readonly MCPToolDefinition[];
   readonly enabledNames: ReadonlySet<string>;
+  readonly deferred: boolean;
 }
 
 export interface IAgentMcpService {

packages/agent-core-v2/src/agent/mcp/mcpService.ts

@@ -212,6 +212,7 @@ export class AgentMcpService extends Service implements IAgentMcpService {
       resolved.client,
       resolved.tools,
       resolved.enabledNames,
+      resolved.deferred,
     );
     this.emitMcpToolCollisions(entry.name, result.collisions);
     this.recordDiscovery(entry.name, resolved.rawTools, resolved.enabledNames, result.collisions);
@@ -235,7 +236,13 @@ export class AgentMcpService extends Service implements IAgentMcpService {
       oauthService,
       reconnect: (signal) => this.reconnect(entry.name, signal),
     });
-    const disposable = this._register(this.registry.register(tool, { source: 'mcp' }));
+    const deferred = this.mcpHandle.connectionManager.configOf(entry.name)?.deferred !== false;
+    const disposable = this._register(
+      this.registry.register(tool, {
+        source: 'mcp',
+        disclosure: deferred ? 'deferred' : 'inline',
+      }),
+    );
     this.mcpTools.set(tool.name, { disposable, serverName: entry.name });
     this.mcpToolsByServer.set(entry.name, [tool.name]);
     void this.dispatcher.dispatch(
@@ -252,6 +259,7 @@ export class AgentMcpService extends Service implements IAgentMcpService {
     client: MCPClient,
     tools: readonly KosongTool[],
     enabledTools: ReadonlySet<string>,
+    deferred: boolean,
   ): {
     readonly registered: readonly string[];
     readonly collisions: readonly McpToolCollision[];
@@ -292,7 +300,7 @@ export class AgentMcpService extends Service implements IAgentMcpService {
             isRemoved: () =>
               this.mcpHandle.connectionManager.get(serverName)?.status === 'removed',
           }),
-          { source: 'mcp' },
+          { source: 'mcp', disclosure: deferred ? 'deferred' : 'inline' },
         ),
       );
       this.mcpTools.set(qualified, { disposable, serverName });

packages/agent-core-v2/src/agent/toolActivation/toolActivationService.ts

@@ -8,6 +8,7 @@ import { IEventBus } from '#/app/event/eventBus';
 import { IAgentProfileService } from '#/agent/profile/profile';
 import { AgentStatusUpdated } from '#/agent/usage/usageEvents';
 import { isToolActive } from '#/agent/toolPolicy/evaluate';
+import { SELECT_TOOLS_TOOL_NAME } from '#/agent/toolSelect/toolSelect';
 import { IAgentToolRegistryService } from '#/agent/toolRegistry/toolRegistry';
 import { AgentToolContribution } from '#/agent/toolRegistry/toolContribution';
 import { ISessionToolPolicyGate } from '#/session/sessionToolPolicyGate/sessionToolPolicyGate';
@@ -55,6 +56,7 @@ export class AgentToolActivationService extends Service implements IAgentToolAct
     if (records.length === 0) return;
     const data = this.profile.data();
     const policy = { tools: data.activeToolNames, disallowedTools: data.disallowedTools };
+    const disclosurePolicy = { disallowedTools: data.disallowedTools };
     const workspaceVeto = { disallowedTools: this.toolPolicyGate.disabledTools };
     this.instantiationService.invokeFunction((accessor) => {
       for (const record of records) {
@@ -63,7 +65,11 @@ export class AgentToolActivationService extends Service implements IAgentToolAct
         if (this.toolRegistry.resolve(options.name) !== undefined) continue;
         if (!this.runtimeAllows(record)) continue;
         if (!isToolActive(workspaceVeto, options.name, source)) continue;
-        if (!isToolActive(policy, options.name, source)) continue;
+        const activeByProfile =
+          options.name === SELECT_TOOLS_TOOL_NAME
+            ? isToolActive(disclosurePolicy, options.name, source)
+            : isToolActive(policy, options.name, source);
+        if (!activeByProfile) continue;
         if (options.when !== undefined && !options.when(accessor)) continue;
         const tool = accessor.get(id);
         const registration = this.toolRegistry.register(tool, {

packages/agent-core-v2/src/agent/toolSelect/toolSelectService.ts

@@ -237,7 +237,7 @@ export class AgentToolSelectService extends Service implements IAgentToolSelectS
   }
 
   private isDynamicallyLoadable(info: ToolInfo): boolean {
-    return info.source === 'mcp' || info.disclosure === 'deferred';
+    return info.disclosure === 'deferred';
   }
 
   private shapeActiveHistory(messages: readonly ContextMessage[]): readonly ContextMessage[] {

packages/agent-core-v2/src/mcpCore/config-schema.ts

@@ -7,6 +7,7 @@ export const McpTimeoutMsSchema = z.number().int().min(1).max(MAX_MCP_TIMEOUT_MS
 
 const McpServerCommonFields = {
   enabled: z.boolean().optional(),
+  deferred: z.boolean().optional(),
   startupTimeoutMs: McpTimeoutMsSchema.optional(),
   toolTimeoutMs: McpTimeoutMsSchema.optional(),
   enabledTools: z.array(z.string()).optional(),

packages/agent-core-v2/src/mcpCore/connection-manager.ts

@@ -41,6 +41,7 @@ export interface McpConnectionView {
   readonly oauthService: McpOAuthService | undefined;
   list(): readonly McpServerEntry[];
   get(name: string): McpServerEntry | undefined;
+  configOf(name: string): McpServerConfig | undefined;
   resolved(
     name: string,
   ):
@@ -49,6 +50,7 @@ export interface McpConnectionView {
         tools: readonly Tool[];
         rawTools: readonly MCPToolDefinition[];
         enabledNames: ReadonlySet<string>;
+        deferred: boolean;
       }
     | undefined;
   getRemoteServerUrl(name: string): string | undefined;
@@ -144,6 +146,7 @@ export class McpConnectionManager implements McpConnectionView {
         tools: readonly Tool[];
         rawTools: readonly MCPToolDefinition[];
         enabledNames: ReadonlySet<string>;
+        deferred: boolean;
       }
     | undefined {
     const entry = this.entries.get(name);
@@ -160,6 +163,7 @@ export class McpConnectionManager implements McpConnectionView {
       tools: entry.tools,
       rawTools: entry.rawTools,
       enabledNames: entry.enabledNames ?? new Set(entry.tools.map((t) => t.name)),
+      deferred: entry.config.deferred !== false,
     };
   }
 

packages/agent-core-v2/src/session/mcp/mergedConnectionView.ts

@@ -4,6 +4,7 @@ import type {
   McpServerEntry,
   McpStatusListener,
 } from '#/mcpCore/connection-manager';
+import type { McpServerConfig } from '#/mcpCore/config-schema';
 import type { McpOAuthService } from '#/mcpCore/oauth/service';
 import { abortable } from '#/_base/utils/abort';
 
@@ -27,6 +28,10 @@ export class MergedMcpConnectionView implements McpConnectionView {
     return this.owner(name).get(name);
   }
 
+  configOf(name: string): McpServerConfig | undefined {
+    return this.owner(name).configOf(name);
+  }
+
   resolved(name: string): ReturnType<McpConnectionView['resolved']> {
     return this.owner(name).resolved(name);
   }

packages/agent-core-v2/test/agent/fullCompaction/fullCompaction.test.ts

@@ -2114,7 +2114,7 @@ describe('FullCompaction', () => {
     });
     const registration = ctx
       .get(IAgentToolRegistryService)
-      .register(mcpTool(LARGE_MCP_TOOL, parameters), { source: 'mcp' });
+      .register(mcpTool(LARGE_MCP_TOOL, parameters), { source: 'mcp', disclosure: 'deferred' });
     try {
       ctx.context.append({
         role: 'system',

packages/agent-core-v2/test/agent/mcp/mcp.test.ts

@@ -15,6 +15,7 @@ import type { Event2 } from '#/app/event/event2';
 import { IEventBus } from '#/app/event/eventBus';
 import { ITelemetryService } from '#/app/telemetry/telemetry';
 import type { McpConnectionManager, McpServerEntry } from '#/mcpCore/connection-manager';
+import type { McpServerConfig } from '#/mcpCore/config-schema';
 import { IAgentMcpService } from '#/agent/mcp/mcp';
 import { renderToolResultForModel } from '#/agent/contextMemory/toolResultRender';
 import { AgentMcpService } from '#/agent/mcp/mcpService';
@@ -57,10 +58,12 @@ interface ResolvedServer {
   readonly tools: readonly KosongTool[];
   readonly rawTools: readonly MCPToolDefinition[];
   readonly enabledNames: ReadonlySet<string>;
+  readonly deferred: boolean;
 }
 
 class FakeMcpManager {
   private readonly entries = new Map<string, McpServerEntry>();
+  private readonly configs = new Map<string, McpServerConfig>();
   private readonly resolvedEntries = new Map<string, ResolvedServer>();
   private readonly listeners = new Set<(entry: McpServerEntry) => void>();
   readonly oauthService: McpOAuthService | undefined;
@@ -77,6 +80,10 @@ class FakeMcpManager {
     return this.entries.get(name);
   }
 
+  configOf(name: string): McpServerConfig | undefined {
+    return this.configs.get(name);
+  }
+
   resolved(name: string): ResolvedServer | undefined {
     if (this.entries.get(name)?.status !== 'connected') return undefined;
     return this.resolvedEntries.get(name);
@@ -125,6 +132,7 @@ class FakeMcpManager {
     tools: readonly KosongTool[],
     enabledNames = new Set(tools.map((tool) => tool.name)),
     rawTools?: readonly MCPToolDefinition[],
+    deferred = true,
   ): void {
     const resolvedRawTools =
       rawTools ??
@@ -138,6 +146,7 @@ class FakeMcpManager {
       tools,
       rawTools: resolvedRawTools,
       enabledNames,
+      deferred,
     });
   }
 
@@ -153,7 +162,10 @@ class FakeMcpManager {
     this.emit(entry);
   }
 
-  needsAuth(name = 'needs-auth'): void {
+  needsAuth(name = 'needs-auth', options: { readonly deferred?: boolean } = {}): void {
+    if (options.deferred !== undefined) {
+      this.configs.set(name, { deferred: options.deferred } as unknown as McpServerConfig);
+    }
     const entry: McpServerEntry = {
       name,
       transport: 'http',
@@ -321,6 +333,7 @@ describe('AgentMcpService', () => {
       'mcp__local_server__echo',
       'mcp__local_server__noop',
     ]);
+    expect(infos.every((info) => info.disclosure === 'deferred')).toBe(true);
     expect(events).toContainEqual(
       expect.objectContaining({
         type: 'tool.list.updated',
@@ -364,6 +377,19 @@ describe('AgentMcpService', () => {
     }
   });
 
+  it('registers tools of a deferred=false server with inline disclosure', async () => {
+    const manager = new FakeMcpManager();
+    const client = fakeMcpClient();
+    manager.setResolved('s', client, await discoverTools(client), undefined, undefined, false);
+    createService(manager);
+
+    manager.connect('s');
+
+    const infos = ix.get(IAgentToolRegistryService).list().filter((tool) => tool.source === 'mcp');
+    expect(infos.length).toBeGreaterThan(0);
+    expect(infos.every((info) => info.disclosure === 'inline')).toBe(true);
+  });
+
   it('ignores status changes from servers outside the session baseline', async () => {
     const manager = new FakeMcpManager();
     const lateClient = fakeMcpClient();
@@ -1223,7 +1249,7 @@ describe('AgentMcpService', () => {
     expect(receivedSignal).toBe(controller.signal);
   });
 
-  it('registers a synthetic authenticate tool when a server needs auth', () => {
+  it('registers a synthetic authenticate tool inline when the server declares deferred: false', () => {
     const oauthService = {
       beginAuthorization: async () => ({
         authorizationUrl: new URL('https://example.com/authorize'),
@@ -1234,13 +1260,14 @@ describe('AgentMcpService', () => {
     const manager = new FakeMcpManager({ oauthService });
     createService(manager);
 
-    manager.needsAuth();
+    manager.needsAuth('needs-auth', { deferred: false });
 
     const tools = ix.get(IAgentToolRegistryService).list();
     expect(tools).toEqual([
       expect.objectContaining({
         name: 'mcp__needs-auth__authenticate',
         source: 'mcp',
+        disclosure: 'inline',
       }),
     ]);
   });
@@ -1263,6 +1290,7 @@ describe('AgentMcpService', () => {
       expect.objectContaining({
         name: 'mcp__needs-auth__authenticate',
         source: 'mcp',
+        disclosure: 'deferred',
       }),
     ]);
     expect(events).toContainEqual(