fix(runtime): codex tool loop, full-trajectory events, and protocol fidelity#593
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…idelity Follow-up to #592. Makes the codex runtime work for multi-step tool turns and forward the whole turn faithfully, by aligning the shim and the ADK mapping with the Codex Responses protocol and the genai/ADK event shapes. proxy.py (the Responses shim): - Stream `function_call` output items (output_item.added -> function_call_arguments.delta/.done -> output_item.done). Previously only message/reasoning were streamed, so a tool call was dropped and the turn ended at the model's preamble. - Backfill `status="completed"` on replayed assistant messages in `input`; Ark's Responses API requires it (MissingParameter: input.status) and Codex replays them without it on multi-step turns. translate.py (result -> ADK events): - Forward every Codex thread item in order instead of collapsing to final_response: reasoning -> thought text; commandExecution / mcpToolCall / dynamicToolCall / fileChange / webSearch -> function_call + function_response; agentMessage / plan / any text-bearing item -> text; userMessage skipped. - Coerce tool-call arguments to a dict and normalize status enums; fall back to final_response so a turn is never silently empty.
zakahan
approved these changes
Jun 9, 2026
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Follow-up to #592 (the remaining codex-runtime fixes that landed on the branch after #592 was merged).
Makes
Agent(runtime="codex")work for multi-step tool turns and forward the whole turn faithfully, by aligning the shim and the ADK mapping with the Codex Responses protocol and genai/ADK event shapes.proxy.py— the Responses shimfunction_calloutput items (output_item.added→function_call_arguments.delta/.done→output_item.done). Previously onlymessage/reasoningwere streamed, so the model's tool call was dropped, Codex never executed it, and the turn ended at the preamble ("let me look…"). Now the tool loop runs to a real answer.status="completed"on replayed assistant messages ininput. On multi-step turns Codex replays a prior assistant message withoutstatus; Ark's Responses API requires it and rejects withMissingParameter: input.status, which Codex retries until it degrades to a generic "high demand" error. Reproduced (a "state your plan, then ls" prompt failed every time before; 5/5 after).translate.py— Codex result → ADK eventsForward every Codex
ThreadItemin order instead of collapsing tofinal_response, mapping each onto the correct genai part:reasoningPart(text=…, thought=True)commandExecutionfunction_call(exec_command)+function_responsemcpToolCallfunction_call(server.tool)+function_response(result/error)dynamicToolCallfunction_call(namespace.tool)+function_response(content/success)fileChangefunction_call(apply_patch)+function_response(status)webSearchfunction_call(web_search)+function_responseagentMessage/plan/ any text-bearing itemPart(text=…)userMessageTool-call
argumentsare coerced to a dict and status enums normalized to their value. Falls back tofinal_responseso a turn is never silently empty. Previously onlycommandExecutionwas handled, so MCP/dynamic tool calls and file changes were dropped.Verification
A multi-step turn now emits, in order:
thought → text(preamble) → function_call:exec_command → function_response → thought → text(final answer), and returns the real result. ruff + pyright clean.