reddb-io
diff --git a/.changeset/olive-moons-repeat.md b/.changeset/olive-moons-repeat.md
@@ -0,0 +1,5 @@
+---
+"opencode": patch
+---
+
+Apply a provider block's `npm` to every model of that provider, not only to models the same block redeclares. A config that set `npm` together with `options.baseURL` but declared no `models` had its `npm` silently ignored while the `baseURL` was applied, so the catalog's SDK was paired with the configured host — for example the Anthropic `/v1/messages` path sent to an OpenAI-compatible host, which 404s. Omitting `npm` still keeps the catalog package while overriding the host, and a per-model `provider.npm` still wins over the provider-level value.
diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
@@ -1516,6 +1516,21 @@ const layer = Layer.effect(
             )
             parsed.models[modelID] = parsedModel
           }
+          // A provider-level npm selects the SDK for every model of that provider, not just the ones
+          // redeclared above. Leaving catalog models on the catalog package pairs them with an
+          // overridden options.baseURL, producing an endpoint neither source describes. Variants are
+          // regenerated for the new package the same way the redeclare path does it.
+          if (provider.npm !== undefined) {
+            for (const [modelID, model] of Object.entries(parsed.models)) {
+              if (provider.models?.[modelID] !== undefined) continue
+              if (model.api.npm === provider.npm) continue
+              const next = { ...model, api: { ...model.api, npm: provider.npm } }
+              parsed.models[modelID] = {
+                ...next,
+                variants: mapValues(ProviderTransform.variants(next), (v) => v),
+              }
+            }
+          }
           database[providerID] = parsed
         }
 

diff --git a/packages/opencode/test/provider/provider.test.ts b/packages/opencode/test/provider/provider.test.ts
@@ -890,6 +890,70 @@ it.instance(
   },
 )
 
+it.instance(
+  "provider-level npm applies to catalog models the config does not redeclare",
+  Effect.gen(function* () {
+    yield* set("ANTHROPIC_API_KEY", "test-api-key")
+    const providers = yield* list
+    const models = providers[ProviderV2.ID.anthropic].models
+    // Without this the catalog package (@ai-sdk/anthropic) would stay paired with the overridden
+    // baseURL, sending the Anthropic /messages path to an OpenAI-compatible host.
+    for (const model of Object.values(models)) expect(model.api.npm).toBe("@ai-sdk/openai-compatible")
+    expect(providers[ProviderV2.ID.anthropic].options.baseURL).toBe("https://proxy.test/v1")
+  }),
+  {
+    config: {
+      provider: {
+        anthropic: {
+          npm: "@ai-sdk/openai-compatible",
+          options: { baseURL: "https://proxy.test/v1" },
+        },
+      },
+    },
+  },
+)
+
+it.instance(
+  "omitting npm keeps the catalog package while overriding the host",
+  Effect.gen(function* () {
+    yield* set("ANTHROPIC_API_KEY", "test-api-key")
+    const providers = yield* list
+    const models = providers[ProviderV2.ID.anthropic].models
+    for (const model of Object.values(models)) expect(model.api.npm).toBe("@ai-sdk/anthropic")
+    expect(providers[ProviderV2.ID.anthropic].options.baseURL).toBe("https://proxy.test/v1")
+  }),
+  {
+    config: {
+      provider: {
+        anthropic: {
+          options: { baseURL: "https://proxy.test/v1" },
+        },
+      },
+    },
+  },
+)
+
+it.instance(
+  "per-model npm still wins over the provider-level value",
+  Effect.gen(function* () {
+    yield* set("ANTHROPIC_API_KEY", "test-api-key")
+    const providers = yield* list
+    const models = providers[ProviderV2.ID.anthropic].models
+    expect(models["claude-opus-4-5"].api.npm).toBe("@ai-sdk/anthropic")
+    expect(models["claude-haiku-4-5-20251001"].api.npm).toBe("@ai-sdk/openai-compatible")
+  }),
+  {
+    config: {
+      provider: {
+        anthropic: {
+          npm: "@ai-sdk/openai-compatible",
+          models: { "claude-opus-4-5": { provider: { npm: "@ai-sdk/anthropic" } } },
+        },
+      },
+    },
+  },
+)
+
 // Edge cases for model configuration
 
 it.instance(