The agent loop is back to main's tool execution: it only exports runToolCall(), honors isError results, and passes structuredContent through afterToolCall. Nested calls (ctx.executeTool, ids, events with parentToolCallId, the nestedCalls record) live in coding-agent and start on the first call.
AgentSession no longer knows exec or tool_search. Tools adjust the declared loadout through a generic prepareLoadout hook, and codemode and tool_search use it like any other tool.
exec and tool_search move to built-in extensions under src/extensions/ and register inactive (defaultActive: false). The CLI loads them with MCP; SDK sessions add createCodemodeExtension(), createToolSearchExtension(), and createMcpExtension(). Extensions gain pi.getSettings() and model catalog and classifier access on ModelRegistry.
- The exec description spends at most codemode.inlineBudget (default 3000) estimated tokens on tool declarations, filled round-robin across namespaces, cheapest first. Every namespace is listed with its tool count, and the listing says COMPLETE or PARTIAL.
- Scripts find omitted and deferred tools with searchTools(query, { limit, namespace }) and describeTool(name).
- tool_search, an optional built-in modeled on Codex, searches codemode and deferred tools and declares the matches for the next model call through the active tool set, so loads are recorded on the branch.
- Both use a BM25 ranker over Codex's search text (name, description, schema properties, namespace) behind a ToolRanker interface.
The codemode tool is now exec and follows the exec tool of OpenAI Codex, so scripts written for Codex run unchanged:
- // @exec: pragma with yield_time_ms, max_output_tokens (default 10000 tokens) and the pi addition timeout_ms; Codex's grammar and error messages
- text(), image() (data URLs, { image_url }, MCP ImageContent), exit(), ALL_TOOLS, tools under normalized identifiers; console and return values append text
- Results start with Script completed/failed and the wall time; failed scripts return an error result that keeps partial output and appends Script error
- Output over the token budget keeps its start and end like Codex; the full text is spilled to a temp file
- MCP tools resolve to their CallToolResult (isError resolves) and are declared as CallToolResult<T>; bash resolves to { output, exit_code, wall_time_seconds }, also for non-zero exits
- The description uses Codex's layout: helper list, deferred-tool guidance, shared MCP types, one section per tool grouped by namespace (MCP servers, with their instructions)
Adds a built-in, opt-in codemode tool that runs model-written JavaScript in the codemode sandbox. Scripts call the other active tools as tools.<name>(args), including concurrently with Promise.all; only the return value, console output, and images attached with image() reach the model.
Nested calls run through the agent loop via a new AgentToolContext (5th execute argument, ctx.executeTool for extension tools), so argument validation and the beforeToolCall/afterToolCall hooks apply. Hooks and tool_call/tool_result events carry the parent call id.
Tools can declare outputSchema and return structuredContent; codemode passes that to scripts and falls back to text content otherwise. The codemode package gains globals, declaration rendering from JSON Schema, and optional deadlines.
