diff --git a/.changeset/dynamically-loaded-tools-capability.md b/.changeset/dynamically-loaded-tools-capability.md
new file mode 100644
index 0000000000..1ff8e84f24
--- /dev/null
+++ b/.changeset/dynamically-loaded-tools-capability.md
@@ -0,0 +1,7 @@
+---
+"@moonshot-ai/kosong": patch
+"@moonshot-ai/kimi-code": patch
+"@moonshot-ai/kimi-code-sdk": patch
+---
+
+Rename the dynamic tool loading model capability from `select_tools` to `dynamically_loaded_tools`.
diff --git a/apps/kimi-code/scripts/update-catalog.mjs b/apps/kimi-code/scripts/update-catalog.mjs
index 41cfca6fa3..ee43eeafc1 100644
--- a/apps/kimi-code/scripts/update-catalog.mjs
+++ b/apps/kimi-code/scripts/update-catalog.mjs
@@ -24,6 +24,10 @@ const KEEP_MODEL = new Set([
   "reasoning",
   "interleaved",
   "modalities",
+  // Message-level tool declarations capability — kosong's
+  // catalogModelToCapability reads it; stripping it here would silently
+  // disable tool-select for catalog-imported aliases.
+  "dynamically_loaded_tools",
 ]);
 
 function resolveOutputFile(args) {
diff --git a/packages/agent-core/src/agent/context/dynamic-tools.ts b/packages/agent-core/src/agent/context/dynamic-tools.ts
index da4d2282b3..577095231b 100644
--- a/packages/agent-core/src/agent/context/dynamic-tools.ts
+++ b/packages/agent-core/src/agent/context/dynamic-tools.ts
@@ -39,10 +39,10 @@ export function isLoadableToolsAnnouncement(message: ContextMessage): boolean {
  * Shape a history for a consumer that must not see dynamic-tool protocol
  * context: drop the loadable-tools announcements and strip `message.tools`
  * (dropping the message entirely when nothing else remains). Two callers:
- *   - projection for a model without the `select_tools` capability (mid-session
- *     model switch — the canonical history keeps its shape, only the outgoing
- *     view changes; announcements would be noise and even reference a
- *     select_tools tool the model does not have);
+ *   - projection for a model without the dynamically-loaded-tools capability
+ *     (mid-session model switch — the canonical history keeps its shape, only
+ *     the outgoing view changes; announcements would be noise and even
+ *     reference a select_tools tool the model does not have);
  *   - the compaction summarizer input (schemas and announcements are protocol
  *     context, not conversation — summarizing them wastes tokens and risks
  *     leaking schema text into the summary).
diff --git a/packages/agent-core/src/agent/context/index.ts b/packages/agent-core/src/agent/context/index.ts
index b8951ba937..fcf9950517 100644
--- a/packages/agent-core/src/agent/context/index.ts
+++ b/packages/agent-core/src/agent/context/index.ts
@@ -376,11 +376,12 @@ export class ContextMemory {
 
   project(messages: readonly ContextMessage[], options?: ProjectOptions): Message[] {
     // Shape for the current model BEFORE projecting: a model without the
-    // select_tools capability must not see dynamic-tool schema messages or
-    // loadable-tools announcements (the canonical history keeps them; only
-    // this outgoing view is shaped). Must run pre-projection — project()
-    // strips `origin`, the only anchor for the announcements. setModel never
-    // rewrites history, so a mid-session switch degrades/upgrades losslessly.
+    // dynamically-loaded-tools capability must not see dynamic-tool schema
+    // messages or loadable-tools announcements (the canonical history keeps
+    // them; only this outgoing view is shaped). Must run pre-projection —
+    // project() strips `origin`, the only anchor for the announcements.
+    // setModel never rewrites history, so a mid-session switch
+    // degrades/upgrades losslessly.
     const shaped = this.agent.toolSelectEnabled ? messages : stripDynamicToolContext(messages);
     const anomalies: ProjectionAnomaly[] = [];
     const result = project(this.agent.microCompaction.compact(shaped), {
diff --git a/packages/agent-core/src/agent/index.ts b/packages/agent-core/src/agent/index.ts
index 6b9d7cf19f..db3e6de282 100644
--- a/packages/agent-core/src/agent/index.ts
+++ b/packages/agent-core/src/agent/index.ts
@@ -236,18 +236,19 @@ export class Agent {
 
   /**
    * Single decision point for select_tools progressive disclosure. All three
-   * gates must be open: the model declares the `select_tools` capability, the
-   * model declares `tool_use` (a model without tool use registering
-   * select_tools is a contradiction), and the `tool-select` experimental flag
-   * is on. Every consumer — top-level tools[] convergence, select_tools
-   * registration, manifest announcements, projection shaping — reads this
-   * instead of re-deriving the conditions, so degradation is lossless: any
-   * closed gate reproduces the inline behavior byte-for-byte.
+   * gates must be open: the model has the `dynamically_loaded_tools`
+   * capability (message-level tool declarations), the model declares
+   * `tool_use` (a model without tool use loading tools dynamically is a
+   * contradiction), and the `tool-select` experimental flag is on. Every
+   * consumer — top-level tools[] convergence, select_tools registration,
+   * manifest announcements, projection shaping — reads this instead of
+   * re-deriving the conditions, so degradation is lossless: any closed gate
+   * reproduces the inline behavior byte-for-byte.
    */
   get toolSelectEnabled(): boolean {
     const capability = this.config.modelCapabilities;
     return (
-      capability.select_tools === true &&
+      capability.dynamically_loaded_tools === true &&
       capability.tool_use &&
       this.experimentalFlags.enabled('tool-select')
     );
diff --git a/packages/agent-core/src/flags/registry.ts b/packages/agent-core/src/flags/registry.ts
index 8a5fd1b3e8..dbec75b80b 100644
--- a/packages/agent-core/src/flags/registry.ts
+++ b/packages/agent-core/src/flags/registry.ts
@@ -27,7 +27,7 @@ export const FLAG_DEFINITIONS = [
     id: 'tool-select',
     title: 'Tool select (progressive tool disclosure)',
     description:
-      'Keep MCP tool schemas out of the immutable top-level tools[]; the model loads them on demand via the select_tools tool. Only takes effect on models whose capability catalog declares select_tools.',
+      'Keep MCP tool schemas out of the immutable top-level tools[]; the model loads them on demand via the select_tools tool. Only takes effect on models whose capability catalog declares dynamically loaded tools.',
     env: 'KIMI_CODE_EXPERIMENTAL_TOOL_SELECT',
     default: false,
     surface: 'core',
diff --git a/packages/agent-core/src/session/provider-manager.ts b/packages/agent-core/src/session/provider-manager.ts
index b67aef3189..072ff44b11 100644
--- a/packages/agent-core/src/session/provider-manager.ts
+++ b/packages/agent-core/src/session/provider-manager.ts
@@ -233,10 +233,12 @@ function resolveModelCapabilities(
     thinking: declared.has('thinking') || declared.has('always_thinking') || detected.thinking,
     tool_use: declared.has('tool_use') || detected.tool_use,
     max_context_tokens: alias.maxContextSize,
-    // Message-level tool declarations (select_tools progressive disclosure).
-    // Every field here must be merged explicitly — a capability registered in
+    // Message-level tool declarations ("dynamically loaded tools"). Every
+    // field here must be merged explicitly — a capability registered in
     // kosong that is not forwarded here never reaches the agent.
-    select_tools: declared.has('select_tools') || detected.select_tools === true,
+    dynamically_loaded_tools:
+      declared.has('dynamically_loaded_tools') ||
+      detected.dynamically_loaded_tools === true,
   };
 }
 
diff --git a/packages/agent-core/test/agent/harness/agent.ts b/packages/agent-core/test/agent/harness/agent.ts
index f3ccef4c35..06041c2599 100644
--- a/packages/agent-core/test/agent/harness/agent.ts
+++ b/packages/agent-core/test/agent/harness/agent.ts
@@ -1094,7 +1094,7 @@ function capabilityNames(capabilities: ModelCapability | undefined): string[] {
     capabilities.audio_in ? 'audio_in' : undefined,
     capabilities.thinking ? 'thinking' : undefined,
     capabilities.tool_use ? 'tool_use' : undefined,
-    capabilities.select_tools === true ? 'select_tools' : undefined,
+    capabilities.dynamically_loaded_tools === true ? 'dynamically_loaded_tools' : undefined,
   ].filter((capability): capability is string => capability !== undefined);
 }
 
diff --git a/packages/agent-core/test/agent/tool-select.e2e.test.ts b/packages/agent-core/test/agent/tool-select.e2e.test.ts
index e26a0082f6..288f132189 100644
--- a/packages/agent-core/test/agent/tool-select.e2e.test.ts
+++ b/packages/agent-core/test/agent/tool-select.e2e.test.ts
@@ -2,7 +2,7 @@
  * select_tools progressive disclosure — end-to-end agent tests.
  *
  * Uses the scripted-generate harness: real ToolManager/turn loop/context, fake
- * LLM. The three-condition gate (model capability.select_tools ×
+ * LLM. The three-condition gate (model capability.dynamically_loaded_tools ×
  * capability.tool_use × `tool-select` flag) is driven through the alias
  * capability declarations and an injected FlagResolver.
  *
@@ -34,7 +34,7 @@ const DISCLOSURE_CAPABILITIES = {
   thinking: false,
   tool_use: true,
   max_context_tokens: 256_000,
-  select_tools: true,
+  dynamically_loaded_tools: true,
 } as const;
 
 const INLINE_PROVIDER = { type: 'kimi', apiKey: 'test-key', model: 'inline-model' } as const;
diff --git a/packages/kosong/src/capability.ts b/packages/kosong/src/capability.ts
index 27d004860d..2f2299b88f 100644
--- a/packages/kosong/src/capability.ts
+++ b/packages/kosong/src/capability.ts
@@ -16,12 +16,13 @@ export interface ModelCapability {
   readonly tool_use: boolean;
   readonly max_context_tokens: number;
   /**
-   * Model accepts message-level tool declarations (`messages[].tools`), the
-   * primitive behind select_tools progressive disclosure. Absent means
-   * unsupported: only models explicitly catalogued or declared with this
-   * capability may ever receive a message carrying `tools`.
+   * Model accepts message-level tool declarations (`messages[].tools`) — the
+   * "dynamically loaded tools" wire feature that clients can drive with
+   * progressive tool disclosure. Absent means unsupported: only models
+   * explicitly catalogued or declared with this capability may ever receive a
+   * message carrying `tools`.
    */
-  readonly select_tools?: boolean;
+  readonly dynamically_loaded_tools?: boolean;
 }
 
 const UNKNOWN_CAPABILITY_MARKER = Symbol.for('moonshot-ai.kosong.UNKNOWN_CAPABILITY');
@@ -40,7 +41,7 @@ export const UNKNOWN_CAPABILITY: ModelCapability = Object.freeze(
       thinking: false,
       tool_use: false,
       max_context_tokens: 0,
-      select_tools: false,
+      dynamically_loaded_tools: false,
     },
     UNKNOWN_CAPABILITY_MARKER,
     { value: true },
@@ -58,7 +59,7 @@ export function isUnknownCapability(capability: ModelCapability): boolean {
     !capability.audio_in &&
     !capability.thinking &&
     !capability.tool_use &&
-    capability.select_tools !== true &&
+    capability.dynamically_loaded_tools !== true &&
     capability.max_context_tokens === 0
   );
 }
diff --git a/packages/kosong/src/catalog.ts b/packages/kosong/src/catalog.ts
index ff1fb94379..ebb2e1daad 100644
--- a/packages/kosong/src/catalog.ts
+++ b/packages/kosong/src/catalog.ts
@@ -14,7 +14,7 @@ export interface CatalogModelEntry {
   readonly tool_call?: boolean;
   readonly reasoning?: boolean;
   /** Accepts message-level tool declarations (`messages[].tools`). Defaults to false. */
-  readonly select_tools?: boolean;
+  readonly dynamically_loaded_tools?: boolean;
   readonly interleaved?: boolean | { readonly field?: string };
   readonly modalities?: {
     readonly input?: readonly string[];
@@ -138,7 +138,7 @@ export function catalogModelToCapability(model: CatalogModelEntry): CatalogModel
       thinking: Boolean(model.reasoning),
       tool_use: model.tool_call ?? true,
       max_context_tokens: context,
-      select_tools: model.select_tools === true,
+      dynamically_loaded_tools: model.dynamically_loaded_tools === true,
     },
   };
 }
diff --git a/packages/kosong/src/index.ts b/packages/kosong/src/index.ts
index 01662bcbc7..e6bd57e627 100644
--- a/packages/kosong/src/index.ts
+++ b/packages/kosong/src/index.ts
@@ -34,7 +34,7 @@ export { KimiChatProvider } from './providers/kimi';
 export type { ExtraBody, GenerationKwargs, KimiOptions, ThinkingConfig } from './providers/kimi';
 
 // Model capability matrix
-export { UNKNOWN_CAPABILITY, isUnknownCapability } from './capability';
+export { isUnknownCapability, UNKNOWN_CAPABILITY } from './capability';
 export type { ModelCapability } from './capability';
 
 // Model catalog (models.dev-style) metadata
diff --git a/packages/kosong/test/catalog.test.ts b/packages/kosong/test/catalog.test.ts
index 5afe778236..87538b92a3 100644
--- a/packages/kosong/test/catalog.test.ts
+++ b/packages/kosong/test/catalog.test.ts
@@ -82,7 +82,7 @@ describe('catalogModelToCapability', () => {
         thinking: true,
         tool_use: true,
         max_context_tokens: 200000,
-        select_tools: false,
+        dynamically_loaded_tools: false,
       },
     });
   });
diff --git a/packages/kosong/test/select-tools.test.ts b/packages/kosong/test/select-tools.test.ts
index 1ce7ff3af7..9d2706eb96 100644
--- a/packages/kosong/test/select-tools.test.ts
+++ b/packages/kosong/test/select-tools.test.ts
@@ -7,7 +7,7 @@
  *     normalization and the `$` builtin branch shared with top-level tools);
  *   - `Tool.deferred` stripping in `generate()` (single strip point for every
  *     provider call — the marker itself must never reach the wire);
- *   - the `select_tools` capability bit (unknown/default-off semantics).
+ *   - the `dynamically_loaded_tools` capability bit (unknown/default-off semantics).
  */
 
 import { UNKNOWN_CAPABILITY, isUnknownCapability } from '#/capability';
@@ -324,30 +324,32 @@ describe('providers without message-level tool declarations', () => {
   });
 });
 
-describe('select_tools capability bit', () => {
+describe('dynamically_loaded_tools capability bit', () => {
+  const BASE_CAPABILITY = {
+    image_in: false,
+    video_in: false,
+    audio_in: false,
+    thinking: false,
+    tool_use: false,
+    max_context_tokens: 0,
+  };
+
   it('defaults to false on UNKNOWN_CAPABILITY', () => {
-    expect(UNKNOWN_CAPABILITY.select_tools).toBe(false);
+    expect(UNKNOWN_CAPABILITY.dynamically_loaded_tools).toBe(false);
   });
 
-  it('a capability that only has select_tools is not "unknown"', () => {
-    expect(
-      isUnknownCapability({
-        image_in: false,
-        video_in: false,
-        audio_in: false,
-        thinking: false,
-        tool_use: false,
-        max_context_tokens: 0,
-        select_tools: true,
-      }),
-    ).toBe(false);
+  it('a capability that only has the bit set is not "unknown"', () => {
+    expect(isUnknownCapability({ ...BASE_CAPABILITY, dynamically_loaded_tools: true })).toBe(
+      false,
+    );
   });
 
-  it('catalog entries map select_tools and default it to false', () => {
+  it('catalog entries map the capability, defaulting to false', () => {
     const base = { id: 'm', limit: { context: 1000 } };
-    expect(catalogModelToCapability(base)?.capability.select_tools).toBe(false);
+    expect(catalogModelToCapability(base)?.capability.dynamically_loaded_tools).toBe(false);
     expect(
-      catalogModelToCapability({ ...base, select_tools: true })?.capability.select_tools,
+      catalogModelToCapability({ ...base, dynamically_loaded_tools: true })?.capability
+        .dynamically_loaded_tools,
     ).toBe(true);
   });
 });
diff --git a/packages/node-sdk/src/catalog.ts b/packages/node-sdk/src/catalog.ts
index f7a215e7c9..592a1647f4 100644
--- a/packages/node-sdk/src/catalog.ts
+++ b/packages/node-sdk/src/catalog.ts
@@ -47,7 +47,7 @@ function capabilityToStrings(capability: ModelCapability): string[] | undefined
   if (capability.audio_in) caps.push('audio_in');
   if (capability.thinking) caps.push('thinking');
   if (capability.tool_use) caps.push('tool_use');
-  if (capability.select_tools === true) caps.push('select_tools');
+  if (capability.dynamically_loaded_tools === true) caps.push('dynamically_loaded_tools');
   return caps.length > 0 ? caps : undefined;
 }
 
diff --git a/packages/node-sdk/test/config.test.ts b/packages/node-sdk/test/config.test.ts
index 0601950548..9484facf1f 100644
--- a/packages/node-sdk/test/config.test.ts
+++ b/packages/node-sdk/test/config.test.ts
@@ -338,7 +338,7 @@ describe('KimiHarness config API', () => {
         id: 'tool-select',
         title: 'Tool select (progressive tool disclosure)',
         description:
-          'Keep MCP tool schemas out of the immutable top-level tools[]; the model loads them on demand via the select_tools tool. Only takes effect on models whose capability catalog declares select_tools.',
+          'Keep MCP tool schemas out of the immutable top-level tools[]; the model loads them on demand via the select_tools tool. Only takes effect on models whose capability catalog declares dynamically loaded tools.',
         surface: 'core',
         env: 'KIMI_CODE_EXPERIMENTAL_TOOL_SELECT',
         defaultEnabled: false,