Codex Tools API

The Codex MCP server exposes three tools.

codex

Send a prompt to OpenAI Codex for code generation or analysis.

Parameters

Parameter	Type	Required	Description
prompt	string	Yes	The prompt to send to Codex

Response

Plain text string with Codex's response.

Example

Input:

{
  "prompt": "Write a TypeScript function that debounces an async function and returns the result of the last invocation"
}

code_review

Send a diff for structured review. Uses agent instructions from ~/.codex/agents/code-reviewer.toml if available.

Parameters

Parameter	Type	Required	Description
diff	string	Yes	The git diff to review (max 500KB)
context	string	No	Additional context for the review

Response

JSON when the response is parseable, otherwise plain text. The JSON structure matches:

interface ReviewResult {
  verdict: "APPROVED" | "NEEDS_REVISION";
  issues: ReviewIssue[];
  suggestions: string[];
}

codex_reply

Continue a previous conversation.

Parameters

Parameter	Type	Required	Description
conversation_id	string	Yes	Identifier for the conversation
reply	string	Yes	The follow-up message

Response

Plain text string with Codex's response.

note

This tool is stateless. The conversation_id is passed as context to Codex but the server does not maintain conversation state between calls.