# LangChain and CrewAI Wrap the function that actually performs the effect. Telemetry callbacks that only record a denied decision do not prevent the function from running. ## Availability | Framework | TypeScript | Python | Go / Rust | | --- | --- | --- | --- | | LangChain | `wrapLangChainTool`, `createLangChainCallbackHandler` | `hush_tool` | Use the ordinary guard at your handler | | CrewAI | No dedicated adapter | `secure_tool` | Use the ordinary guard at your handler | These adapters use structural interfaces without importing LangChain or CrewAI. Check the framework's dispatch lifecycle in your application. ## TypeScript wrapping `wrapLangChainTool(tool, guard)` gates `invoke`, `call`, and `func` and preserves the tool's prototype and fields. The returned proxy enforces before calling the original method. The callback handler asks the framework to raise errors and await handlers; verify that your selected executor respects both. Run [adapters.mjs](https://hushspec.org/docs-examples/sdks/typescript/adapters.mjs) as described in the [structural adapter test](openai.md#executable-boundary-test). A blocked tool's asynchronous handler is never called. ## Python argument mapping For the default `tool_call` action, decorators measure the actual bound positional/keyword arguments and use the configured tool name. For another action type, pass `action_mapper(args, kwargs)` returning an `EvaluationAction` with the correct type and a nonempty target. Do not infer filesystem authority from a Python function's name. Download [adapters.py](https://hushspec.org/docs-examples/sdks/python/adapters.py) and use the [Python SDK setup](../sdks/python.md). Run `python adapters.py policy.yaml`. The test covers both decorators, a protected-path mapper, and refusal when a non-tool action lacks a mapper. The dispatch list remains empty on every refusal. ## Lifecycle and error handling Let `HushSpecDenied` stop the call. Do not catch it and then execute the same handler as a fallback. Preserve a useful model-facing refusal and retain the operator's evidence. Close a watching Python guard when the application stops; stop TypeScript providers separately. Warnings need affirmative confirmation, and custom callbacks must obey the [same-guard non-reentrancy contract](../hot-reload.md). A framework wrapper does not mediate effects performed elsewhere in the process.