fix(coding-agent): honor registered model base urls

closes #4063

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed `pi.registerProvider()` to honor per-model `baseUrl` overrides ([#4063](https://github.com/badlogic/pi-mono/issues/4063)).
+
 ## [0.71.1] - 2026-05-01
 
 ### Added

packages/coding-agent/docs/custom-provider.md

@@ -595,6 +595,9 @@ interface ProviderModelConfig {
   /** API type override for this specific model. */
   api?: Api;
 
+  /** API endpoint URL override for this specific model. */
+  baseUrl?: string;
+
   /** Whether the model supports extended thinking. */
   reasoning: boolean;
 

packages/coding-agent/docs/extensions.md

@@ -1602,7 +1602,7 @@ pi.registerProvider("corporate-ai", {
 - `api` - API type: `"anthropic-messages"`, `"openai-completions"`, `"openai-responses"`, etc.
 - `headers` - Custom headers to include in requests.
 - `authHeader` - If true, adds `Authorization: Bearer` header automatically.
-- `models` - Array of model definitions. If provided, replaces all existing models for this provider.
+- `models` - Array of model definitions. If provided, replaces all existing models for this provider. Model definitions can set `baseUrl` to override the provider endpoint for that model.
 - `oauth` - OAuth provider config for `/login` support. When provided, the provider appears in the login menu.
 - `streamSimple` - Custom streaming implementation for non-standard APIs.
 

packages/coding-agent/src/core/extensions/types.ts

@@ -1355,6 +1355,8 @@ export interface ProviderModelConfig {
 	name: string;
 	/** API type override for this model. */
 	api?: Api;
+	/** API endpoint URL override for this model. */
+	baseUrl?: string;
 	/** Whether the model supports extended thinking. */
 	reasoning: boolean;
 	/** Supported input types. */

packages/coding-agent/src/core/model-registry.ts

@@ -876,7 +876,7 @@ export class ModelRegistry {
 					name: modelDef.name,
 					api: api as Api,
 					provider: providerName,
-					baseUrl: config.baseUrl!,
+					baseUrl: modelDef.baseUrl ?? config.baseUrl!,
 					reasoning: modelDef.reasoning,
 					input: modelDef.input as ("text" | "image")[],
 					cost: modelDef.cost,