new_pull

packages/ai/README.md

@@ -478,6 +478,40 @@ const bookMeetingTool: Tool = {
 };
 ```
 
+### Constrained Sampling for Tools
+
+Tools can opt in to provider-side constrained sampling. For JSON-schema tools, `strict: 'prefer'` uses provider-side strict schema enforcement when supported and otherwise falls back to normal tool calling. `strict: 'require'` fails the request when the active provider/model cannot honor it. Set `constrainedSampling: false` to explicitly opt out; it behaves the same as omitting the field.
+
+```typescript
+const strictTool: Tool = {
+  name: 'edit_file',
+  description: 'Edit a file',
+  parameters: Type.Object({
+    path: Type.String(),
+    content: Type.String()
+  }, { additionalProperties: false }),
+  constrainedSampling: { type: 'json_schema', strict: 'prefer' }
+};
+```
+
+Strict JSON-schema constrained sampling is supported for OpenAI, Anthropic, supported Amazon Bedrock Converse models, Mistral, and Gemini 3 tool calls through the Google Generative AI and Vertex adapters. Google uses `VALIDATED` function-calling mode (or `ANY` when explicitly requested); earlier Gemini versions fall back for `strict: 'prefer'` and reject `strict: 'require'` because they do not enforce required parameters. Bedrock strict-tool capability is generated from model structured-output metadata; custom Bedrock models can override `compat.supportsStrictMode`. OpenAI Responses and Chat Completions can also emit grammar-constrained custom tools with OpenAI Lark or regex grammar variants. If multiple OpenAI variants are supplied, Lark is preferred over regex. Grammar constraints are enforced when the active model supports grammar tools; otherwise the tool falls back to normal function/JSON-schema handling. Grammar tool capability is model metadata: the generated catalog sets `compat.supportsOpenAIGrammarTools` for GPT-5+ models on endpoints that pass OpenAI custom tools through (OpenAI, OpenAI Codex, Azure OpenAI Responses, GitHub Copilot, opencode, and Cloudflare AI Gateway). OpenAI rejects `type: "custom"` tools for pre-GPT-5 models, and gateways that normalize tool schemas (e.g. OpenRouter) mangle them, so the flag stays off elsewhere. Custom model definitions can opt in via `compat`. Grammar-capable models reject grammar configurations without a non-empty supported variant. Native grammar tools must have an object parameter schema with exactly one required string property:
+
+```typescript
+const patchTool: Tool = {
+  name: 'apply_patch',
+  description: 'Apply a patch',
+  parameters: Type.Object({
+    input: Type.String()
+  }, { additionalProperties: false }),
+  constrainedSampling: {
+    type: 'grammar',
+    variants: {
+      openai_lark: 'start: /.+/s'
+    }
+  }
+};
+```
+
 ### Handling Tool Calls
 
 Tool results use content blocks and can include both text and images:
@@ -1124,6 +1158,7 @@ interface OpenAICompletionsCompat {
   supportsReasoningEffort?: boolean; // Whether provider supports `reasoning_effort` (default: true)
   supportsUsageInStreaming?: boolean; // Whether provider supports `stream_options: { include_usage: true }` (default: true)
   supportsStrictMode?: boolean;      // Whether provider supports `strict` in tool definitions (default: true)
+  supportsOpenAIGrammarTools?: boolean; // Whether to emit OpenAI custom Lark/regex grammar tools; false falls back to normal function tools (default: false; the generated catalog enables it for capable models)
   sendSessionAffinityHeaders?: boolean; // Send session-affinity data from `sessionId` (default: false)
   sessionAffinityFormat?: 'openai' | 'openai-nosession' | 'openrouter'; // Format for session affinity: 'openai' uses `prompt_cache_key`, `session_id`, `x-client-request-id`, and `x-session-affinity`; 'openai-nosession' uses `prompt_cache_key`, `x-client-request-id`, and `x-session-affinity`; 'openrouter' uses `x-session-id` (default: auto-detected)
   maxTokensField?: 'max_completion_tokens' | 'max_tokens';  // Which field name to use (default: max_completion_tokens)
@@ -1142,6 +1177,8 @@ interface OpenAIResponsesCompat {
   supportsDeveloperRole?: boolean;   // Whether provider supports `developer` role vs `system` (default: true)
   sessionAffinityFormat?: 'openai' | 'openai-nosession' | 'openrouter'; // Session-affinity header format: 'openai' sends `session_id` and `x-client-request-id`; 'openai-nosession' sends `x-client-request-id`; 'openrouter' sends `x-session-id`. Does not affect the `prompt_cache_key` body param (default: auto-detected)
   supportsLongCacheRetention?: boolean; // Whether provider supports `prompt_cache_retention: "24h"` (default: true)
+  supportsStrictMode?: boolean;      // Whether provider supports strict JSON-schema function tools (default: false; enabled in metadata for built-in OpenAI models)
+  supportsOpenAIGrammarTools?: boolean; // Whether to emit OpenAI custom Lark/regex grammar tools; false falls back to normal function tools (default: false; the generated catalog enables it for capable models)
 }
 ```
 
@@ -1500,7 +1537,7 @@ Built-in login and refresh flows are private provider implementations. Use provi
 
 Provider notes:
 
-**OpenAI Codex**: Requires a ChatGPT Plus or Pro subscription. Provides access to GPT-5.x Codex models with extended context windows and reasoning capabilities. The library automatically handles session-based prompt caching when `sessionId` is provided in stream options. You can set `transport` in stream options to `"sse"`, `"websocket"`, or `"auto"` for Codex Responses transport selection. When using WebSocket with a `sessionId`, connections are reused per session and expire after 5 minutes of inactivity.
+**OpenAI Codex**: Requires a ChatGPT Plus or Pro subscription. Provides access to GPT-5.x Codex models with extended context windows and reasoning capabilities. The library automatically handles session-based prompt caching when `sessionId` is provided in stream options unless `cacheRetention` is `"none"`. You can set `transport` in stream options to `"sse"`, `"websocket"`, or `"auto"` for Codex Responses transport selection. When using WebSocket with a `sessionId` and cache retention enabled, connections are reused per session and expire after 5 minutes of inactivity.
 
 **Azure OpenAI (Responses)**: Uses the Responses API only. Set `AZURE_OPENAI_API_KEY` and either `AZURE_OPENAI_BASE_URL` or `AZURE_OPENAI_RESOURCE_NAME`. `AZURE_OPENAI_BASE_URL` supports both `https://<resource>.openai.azure.com` and `https://<resource>.cognitiveservices.azure.com`; root endpoints are normalized to `.../openai/v1` automatically. Use `AZURE_OPENAI_API_VERSION` (defaults to `v1`) to override the API version if needed. Deployment names are treated as model IDs by default, override with `azureDeploymentName` or `AZURE_OPENAI_DEPLOYMENT_NAME_MAP` using comma-separated `model-id=deployment` pairs (for example `gpt-4o-mini=my-deployment,gpt-4o=prod`). Legacy deployment-based URLs are intentionally unsupported.