diff --git a/.changeset/warn-malformed-models-entry.md b/.changeset/warn-malformed-models-entry.md
new file mode 100644
index 00000000000..0b74fb051cd
--- /dev/null
+++ b/.changeset/warn-malformed-models-entry.md
@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Warn at startup when a [models] entry in config.toml is missing the model field and cannot be used.
diff --git a/packages/agent-core-v2/src/app/config/config.ts b/packages/agent-core-v2/src/app/config/config.ts
index 9003c1d36ea..fc0db298859 100644
--- a/packages/agent-core-v2/src/app/config/config.ts
+++ b/packages/agent-core-v2/src/app/config/config.ts
@@ -24,6 +24,8 @@ export interface ConfigKeyDeprecation {
   readonly message?: string;
 }
 
+export type ConfigCollectDiagnostics = (rawSection: unknown) => readonly ConfigDiagnostic[];
+
 export type EnvBindings<T> = EnvBinding | { [K in keyof T]?: EnvBinding | EnvBindings<T[K]> };
 
 export type AnyEnvBindings = EnvBinding | { readonly [key: string]: EnvBinding | AnyEnvBindings };
@@ -93,6 +95,7 @@ export interface ConfigSection<T = unknown> {
   readonly fromToml?: ConfigFromToml;
   readonly toToml?: ConfigToToml;
   readonly deprecations?: readonly ConfigKeyDeprecation[];
+  readonly collectDiagnostics?: ConfigCollectDiagnostics;
 }
 
 export interface RegisterSectionOptions<T> {
@@ -104,6 +107,7 @@ export interface RegisterSectionOptions<T> {
   readonly fromToml?: ConfigFromToml;
   readonly toToml?: ConfigToToml;
   readonly deprecations?: readonly ConfigKeyDeprecation[];
+  readonly collectDiagnostics?: ConfigCollectDiagnostics;
 }
 
 export interface ConfigEffectiveOverlay {
diff --git a/packages/agent-core-v2/src/app/config/configService.ts b/packages/agent-core-v2/src/app/config/configService.ts
index fdc2dc6f5aa..fadb6a96ff5 100644
--- a/packages/agent-core-v2/src/app/config/configService.ts
+++ b/packages/agent-core-v2/src/app/config/configService.ts
@@ -151,7 +151,8 @@ function isSameSection(
     existing.fromToml === options.fromToml &&
     existing.toToml === options.toToml &&
     deepEqual(existing.defaultValue, options.defaultValue) &&
-    deepEqual(existing.deprecations, options.deprecations)
+    deepEqual(existing.deprecations, options.deprecations) &&
+    existing.collectDiagnostics === options.collectDiagnostics
   );
 }
 
@@ -249,6 +250,7 @@ export class ConfigRegistry extends Disposable implements IConfigRegistry {
       fromToml: options.fromToml,
       toToml: options.toToml,
       deprecations: options.deprecations,
+      collectDiagnostics: options.collectDiagnostics,
     });
     this._onDidRegisterSection.fire({ domain });
   }
@@ -576,6 +578,13 @@ export class ConfigService extends Disposable implements IConfigService {
     for (const diagnostic of collectKeyDeprecations(nextRawSnake, this.registry.listSections())) {
       this.pushDiagnostic(diagnostic);
     }
+    for (const section of this.registry.listSections()) {
+      if (section.collectDiagnostics === undefined) continue;
+      const rawSection = nextRawSnake[camelToSnake(section.domain)];
+      for (const diagnostic of section.collectDiagnostics(rawSection)) {
+        this.pushDiagnostic(diagnostic);
+      }
+    }
     if (source !== 'load' && JSON.stringify(nextRawSnake) === JSON.stringify(this.rawSnake)) {
       const scratch = { ...this.validated };
       this.applySectionEnvBindings(scratch, true);
diff --git a/packages/agent-core-v2/src/app/kosongConfig/configSection.ts b/packages/agent-core-v2/src/app/kosongConfig/configSection.ts
index 992e9b3bc67..73b3c548589 100644
--- a/packages/agent-core-v2/src/app/kosongConfig/configSection.ts
+++ b/packages/agent-core-v2/src/app/kosongConfig/configSection.ts
@@ -1,6 +1,7 @@
 import { z } from 'zod';
 
 import {
+  type ConfigDiagnostic,
   type ConfigStripEnv,
   envBindings,
 } from '#/app/config/config';
@@ -195,6 +196,54 @@ type _AssertModelsSection = AssertExact<
   Equal<z.infer<typeof ModelsSectionSchema>, ModelsSection>
 >;
 
+const MODEL_OBJECT_FIELDS = new Set(
+  Object.entries(ModelRecordSchema.shape)
+    .filter(([, field]) => unwrapWrapperSchema(field as z.ZodTypeAny) instanceof z.ZodObject)
+    .map(([key]) => camelToSnake(key)),
+);
+
+function unwrapWrapperSchema(schema: z.ZodTypeAny): z.ZodTypeAny {
+  let current = schema;
+  while (
+    current instanceof z.ZodOptional ||
+    current instanceof z.ZodNullable ||
+    current instanceof z.ZodDefault
+  ) {
+    current = current.unwrap() as z.ZodTypeAny;
+  }
+  return current;
+}
+
+function collectMalformedModelEntries(rawModels: unknown): ConfigDiagnostic[] {
+  if (!isPlainObject(rawModels)) return [];
+  const diagnostics: ConfigDiagnostic[] = [];
+  for (const [alias, entry] of Object.entries(rawModels)) {
+    if (!isPlainObject(entry)) continue;
+    if (entry['model'] !== undefined || entry['name'] !== undefined) continue;
+    diagnostics.push({
+      domain: MODELS_SECTION,
+      severity: 'warning',
+      message: malformedModelMessage(alias, entry),
+    });
+  }
+  return diagnostics;
+}
+
+function malformedModelMessage(alias: string, entry: Record<string, unknown>): string {
+  const base = `[models] entry '${alias}' is missing the 'model' field and cannot be used as a model`;
+  const dottedAlias = dottedAliasSuffix(alias, entry);
+  if (dottedAlias === undefined) return `${base}.`;
+  return `${base}; if the alias contains dots, quote the table name (e.g. [models."${dottedAlias}"]).`;
+}
+
+function dottedAliasSuffix(alias: string, entry: Record<string, unknown>): string | undefined {
+  for (const [key, value] of Object.entries(entry)) {
+    if (MODEL_OBJECT_FIELDS.has(key) || !isPlainObject(value)) continue;
+    return dottedAliasSuffix(`${alias}.${key}`, value) ?? `${alias}.${key}`;
+  }
+  return undefined;
+}
+
 export const modelsFromToml = (rawSnake: unknown): unknown => {
   if (!isPlainObject(rawSnake)) return rawSnake;
   const out: Record<string, unknown> = {};
@@ -255,6 +304,7 @@ registerConfigSection(MODELS_SECTION, ModelsSectionSchema, {
   defaultValue: {},
   fromToml: modelsFromToml,
   toToml: modelsToToml,
+  collectDiagnostics: collectMalformedModelEntries,
 });
 
 export const THINKING_SECTION = 'thinking';
diff --git a/packages/agent-core-v2/test/app/config/config.test.ts b/packages/agent-core-v2/test/app/config/config.test.ts
index d06a9827d36..87dce676ab7 100644
--- a/packages/agent-core-v2/test/app/config/config.test.ts
+++ b/packages/agent-core-v2/test/app/config/config.test.ts
@@ -1373,6 +1373,98 @@ describe('config deprecations', () => {
   });
 });
 
+describe('malformed models config entries', () => {
+  async function createConfig(toml: string) {
+    const disposables = new DisposableStore();
+    const ix = disposables.add(new TestInstantiationService());
+    const storage = new InMemoryStorageService();
+    await storage.write('', 'config.toml', new TextEncoder().encode(toml));
+    ix.stub(ILogService, stubLog());
+    ix.stub(IBootstrapService, stubBootstrap('/tmp/kimi-cfg', {}));
+    ix.stub(IFileSystemStorageService, storage);
+    ix.set(IAtomicTomlDocumentStore, new SyncDescriptor(TomlAtomicDocumentStore));
+    ix.set(IConfigRegistry, new SyncDescriptor(ConfigRegistry));
+    ix.set(IConfigService, new SyncDescriptor(ConfigService));
+    const config = ix.get(IConfigService);
+    await config.ready;
+    return { config, disposables, storage };
+  }
+
+  it('warns at load time when a dotted alias parses as a nested table', async () => {
+    const { config, disposables } = await createConfig(
+      '[models.kimi-k2.7-code]\nmodel = "kimi-k2.7-code"\nmax_context_size = 262144\n',
+    );
+
+    expect(config.diagnostics()).toContainEqual({
+      domain: 'models',
+      severity: 'warning',
+      message:
+        "[models] entry 'kimi-k2' is missing the 'model' field and cannot be used as a model; " +
+        'if the alias contains dots, quote the table name (e.g. [models."kimi-k2.7-code"]).',
+    });
+
+    disposables.dispose();
+  });
+
+  it('stays silent for quoted dotted aliases and entries with a wire-facing name', async () => {
+    const { config, disposables } = await createConfig(
+      '[models."kimi-k2.7-code"]\nmodel = "kimi-k2.7-code"\n\n[models.renamed]\nname = "wire-name"\n',
+    );
+
+    expect(config.diagnostics()).toEqual([]);
+
+    disposables.dispose();
+  });
+
+  it('warns without the dotted-alias hint when the entry has no nested table', async () => {
+    const { config, disposables } = await createConfig(
+      '[models.partial]\nmax_context_size = 262144\n',
+    );
+
+    expect(config.diagnostics()).toContainEqual({
+      domain: 'models',
+      severity: 'warning',
+      message:
+        "[models] entry 'partial' is missing the 'model' field and cannot be used as a model.",
+    });
+
+    disposables.dispose();
+  });
+
+  it('does not mistake schema object fields for a dotted alias', async () => {
+    const { config, disposables } = await createConfig(
+      '[models.partial]\noverrides = { max_output_size = 8192 }\n',
+    );
+
+    expect(config.diagnostics()).toContainEqual({
+      domain: 'models',
+      severity: 'warning',
+      message:
+        "[models] entry 'partial' is missing the 'model' field and cannot be used as a model.",
+    });
+
+    disposables.dispose();
+  });
+
+  it('clears the warning on reload once the entry is fixed', async () => {
+    const { config, disposables, storage } = await createConfig(
+      '[models.kimi-k2.7-code]\nmodel = "kimi-k2.7-code"\n',
+    );
+    expect(config.diagnostics()).toHaveLength(1);
+
+    await storage.write(
+      '',
+      'config.toml',
+      new TextEncoder().encode('[models."kimi-k2.7-code"]\nmodel = "kimi-k2.7-code"\n'),
+    );
+    await config.reload();
+
+    expect(config.diagnostics()).toEqual([]);
+
+    disposables.dispose();
+  });
+});
+
 describe('task config section', () => {
   it('re-applies the keepAliveOnExit env binding on every get()', async () => {
     const env: Record<string, string> = {};
@@ -2445,7 +2537,7 @@ describe('config section collection fold (D12)', () => {
     parse(value: unknown): RuntimeFoldDemo {
       const demo = value as RuntimeFoldDemo;
       if (typeof demo?.enabled !== 'boolean') {
-        throw new Error('runtimeFoldDemo.enabled must be a boolean');
+        throw new TypeError('runtimeFoldDemo.enabled must be a boolean');
       }
       return demo;
     },
@@ -2731,8 +2823,8 @@ describe('ConfigService replaceSections', () => {
       defaultModel: undefined,
       thinking: {},
     });
-    expect([...domains].sort()).toEqual(
-      [PROVIDERS_SECTION, MODELS_SECTION, DEFAULT_MODEL_SECTION, THINKING_SECTION].sort(),
+    expect([...domains].toSorted()).toEqual(
+      [PROVIDERS_SECTION, MODELS_SECTION, DEFAULT_MODEL_SECTION, THINKING_SECTION].toSorted(),
     );
 
     disposables.dispose();
@@ -2810,7 +2902,7 @@ describe('ConfigService persistence guards', () => {
   async function expectPersistBlocked(promise: Promise<unknown>): Promise<void> {
     const error = await promise.then(
       () => undefined,
-      (e: unknown) => e,
+      (error: unknown) => error,
     );
     expect(isError2(error)).toBe(true);
     expect((error as Error2).code).toBe(ErrorCodes.CONFIG_PERSIST_BLOCKED);