## Problem

When LiteLLM converts an OpenAI **Responses API** request to the **Chat Completions API**, several built-in tool types that have no valid equivalent in the Chat Completions spec are silently passed through to the provider. This causes provider-side `400` errors such as:

> "tools[N].type:type is illegal"

### Affected tool types - `local_shell` — Codex CLI built-in shell tool (no Chat Completions equivalent) - `file_search` — OpenAI file search tool (handled separately by emulated handler, but still leaks through in transformation) - `image_generation` — OpenAI image generation tool - `namespace` — Codex CLI 0.130.0 tool namespace - `mcp` — MCP server tools are Responses-API-specific - `code_interpreter` — Has no native Chat Completions equivalent, but previously passed through raw - `computer_use` / `computer_use_preview` — Passed through raw, causing schema validation failures on generic providers - Unknown / passthrough types (e.g. `tool_search`, `code_execution_20250825`, Vertex AI native tools) — silently forwarded

### Repro

```python from litellm.responses.litellm_completion_transformation.transformation import ( LiteLLMCompletionResponsesConfig, )

# This s…