Infer the Anthropic wire from a provider's /anthropic endpoint path

packages/agent-core-v2/src/app/kosongConfig/modelsDev.ts

@@ -254,7 +254,12 @@ function inferDeclaredWireType(entry: ModelsDevProviderEntry): ProviderType | un
   if (isWireType(entry.type)) return entry.type;
   const npm = (entry.npm ?? '').toLowerCase();
   const id = (entry.id ?? '').toLowerCase();
-  if (npm.includes('anthropic') || id.includes('anthropic') || id.includes('claude')) {
+  if (
+    npm.includes('anthropic') ||
+    id.includes('anthropic') ||
+    id.includes('claude') ||
+    hasAnthropicEndpointPath(entry.api)
+  ) {
     return 'anthropic';
   }
   if (id.includes('vertex')) return 'vertexai';
@@ -265,6 +270,24 @@ function inferDeclaredWireType(entry: ModelsDevProviderEntry): ProviderType | un
   return undefined;
 }
 
+/**
+ * Detects the Anthropic wire from the declared endpoint when neither `type`
+ * nor `npm`/`id` names it: vendors that speak OpenAI by default expose their
+ * Anthropic-compatible surface under a dedicated `/anthropic` path segment
+ * (e.g. `https://host/anthropic`). Without this the endpoint falls through to
+ * the OpenAI-compatible fallback and its Anthropic URL is persisted under the
+ * OpenAI wire — an incompatible protocol/base-URL pair. The match is on the
+ * URL path only, so a host such as `api.anthropic.com` (whose path is `/v1`)
+ * is left to the `id`/`npm` checks and never triggers here.
+ */
+function hasAnthropicEndpointPath(api: string | undefined): boolean {
+  if (typeof api !== 'string' || api.length === 0) return false;
+  // Drop the scheme + authority so only the path is inspected; a bare
+  // `anthropic` path segment is the endpoint convention for this wire.
+  const path = api.replace(/^[a-z][a-z0-9+.-]*:\/\/[^/]*/i, '');
+  return /(?:^|\/)anthropic(?:\/|$)/i.test(path);
+}
+
 /**
  * Resolves the base URL to store for a models.dev provider, adapting the
  * directory's `api` to the wire's SDK convention.

packages/agent-core-v2/test/app/kosongConfig/modelsDevImport.test.ts

@@ -80,6 +80,20 @@ const CATALOG = {
       },
     },
   },
+  'anthropic-gateway': {
+    id: 'anthropic-gateway',
+    name: 'Anthropic Gateway',
+    // No `type` and no anthropic token in id/npm: the wire is declared solely
+    // by the `/anthropic` endpoint path.
+    api: 'https://api.example.test/anthropic',
+    models: {
+      'gw-anthropic': {
+        id: 'gw-anthropic',
+        limit: { context: 200000 },
+        modalities: { input: ['text'], output: ['text'] },
+      },
+    },
+  },
 } as const;
 
 const REGISTRY_URL = 'https://internal.example/api.json';
@@ -232,6 +246,22 @@ describe('IModelsDevImportService', () => {
     expect(config.get('defaultModel')).toBe('k2');
   });
 
+  it('imports an entry whose /anthropic endpoint path declares it as an anthropic provider', async () => {
+    setModelsDevUpstreamForTest({ fetchImpl: fetchJson(CATALOG) });
+    const { config, imports } = createHost({ providers: {}, models: {} });
+
+    const item = await imports.getModelsDevProvider('anthropic-gateway');
+    expect(item).toMatchObject({ wire_type: 'anthropic', guessed: false, needs_base_url: false });
+
+    await imports.importModelsDevProvider({ catalogId: 'anthropic-gateway', apiKey: 'sk-test' });
+    const providers = config.inspect<ProvidersSection>(PROVIDERS_SECTION).userValue ?? {};
+    expect(providers['anthropic-gateway']).toMatchObject({
+      type: 'anthropic',
+      baseUrl: 'https://api.example.test/anthropic',
+      apiKey: 'sk-test',
+    });
+  });
+
   it('seeds default_model from the first imported model only when none is configured', async () => {
     setModelsDevUpstreamForTest({ fetchImpl: fetchJson(CATALOG) });
     const { config, imports } = createHost({ providers: {}, models: {} });

packages/kosong/src/catalog.ts

@@ -244,7 +244,12 @@ function inferDeclaredWireType(entry: CatalogProviderEntry): ProviderType | unde
   if (isWireType(entry.type)) return entry.type;
   const npm = (entry.npm ?? '').toLowerCase();
   const id = (entry.id ?? '').toLowerCase();
-  if (npm.includes('anthropic') || id.includes('anthropic') || id.includes('claude')) {
+  if (
+    npm.includes('anthropic') ||
+    id.includes('anthropic') ||
+    id.includes('claude') ||
+    hasAnthropicEndpointPath(entry.api)
+  ) {
     return 'anthropic';
   }
   if (id.includes('vertex')) return 'vertexai';
@@ -255,6 +260,24 @@ function inferDeclaredWireType(entry: CatalogProviderEntry): ProviderType | unde
   return undefined;
 }
 
+/**
+ * Detects the Anthropic wire from the declared endpoint when neither `type`
+ * nor `npm`/`id` names it: vendors that speak OpenAI by default expose their
+ * Anthropic-compatible surface under a dedicated `/anthropic` path segment
+ * (e.g. `https://host/anthropic`). Without this the endpoint falls through to
+ * the OpenAI-compatible fallback and its Anthropic URL is persisted under the
+ * OpenAI wire — an incompatible protocol/base-URL pair. The match is on the
+ * URL path only, so a host such as `api.anthropic.com` (whose path is `/v1`)
+ * is left to the `id`/`npm` checks and never triggers here.
+ */
+function hasAnthropicEndpointPath(api: string | undefined): boolean {
+  if (typeof api !== 'string' || api.length === 0) return false;
+  // Drop the scheme + authority so only the path is inspected; a bare
+  // `anthropic` path segment is the endpoint convention for this wire.
+  const path = api.replace(/^[a-z][a-z0-9+.-]*:\/\/[^/]*/i, '');
+  return /(?:^|\/)anthropic(?:\/|$)/i.test(path);
+}
+
 /**
  * Resolves the base URL to store for a catalog provider, adapting the catalog's
  * `api` to the wire's SDK convention.

packages/kosong/test/catalog.test.ts

@@ -110,6 +110,30 @@ describe('resolveCatalogImport — wire resolution', () => {
       reason: 'proprietary-sdk',
     });
   });
+
+  it('infers anthropic from a declared /anthropic endpoint path when no type or npm/id names it', () => {
+    // A vendor that speaks OpenAI by default but exposes its Anthropic-compatible
+    // surface under a `/anthropic` path: without endpoint inference this fell
+    // through to the OpenAI fallback and the Anthropic URL was persisted under
+    // the OpenAI wire — an incompatible protocol/base-URL pair.
+    expect(
+      resolveCatalogImport({ id: 'gateway', api: 'https://api.example.test/anthropic' }),
+    ).toEqual({
+      kind: 'ok',
+      wire: 'anthropic',
+      guessed: false,
+      baseUrl: 'https://api.example.test/anthropic',
+    });
+    // The regional twin on a different host resolves the same way.
+    expect(
+      resolveCatalogImport({ id: 'gateway', api: 'https://api.example.com/anthropic' }),
+    ).toMatchObject({ kind: 'ok', wire: 'anthropic', guessed: false });
+    // A host that merely contains "anthropic" but serves the OpenAI path is
+    // left to the fallback — the match is on the path, not the host.
+    expect(
+      resolveCatalogImport({ id: 'gateway', api: 'https://anthropic.example.test/v1' }),
+    ).toMatchObject({ kind: 'ok', wire: 'openai', guessed: true });
+  });
 });
 
 describe('resolveCatalogImport — endpoint resolution', () => {