v0.35.7

Changes to note

• Background responses now report in_progress, as the spec says; clients that checked for running should check for in_progress.
• An idempotent replay whose original response is gone now answers 404 response_not_found, not 200 with "status": "unknown".
• A produced file larger than the attachment cap is named in the answer and stays in the task's files. The cap is now 64 MiB (HARNESS_RESP_MAX_FILE_BYTES; it was 25 MiB).
• A cancel answered cancelled now always holds, including one sent the moment a background task starts.
• The conformance suite at this tag is 2026.10.19.post1, which adds T-11 (a background task read mid-turn reports in_progress).

What's Changed

• UHP 2026-10-19, addition: a new task may bring its earlier turns (input_history) by @github-actions[bot] in #520
• UHP 2026-10-19, addition: each turn says when it began and ended (created_at, completed_at) by @github-actions[bot] in #521
• Answer background responses in UHP's status vocabulary by @aswathas in #512
• produced files: one too large to attach is named in the answer, and never read into the gateway by @github-actions[bot] in #522
• cancel: a cancel answered cancelled is never overwritten by the turn's own end by @github-actions[bot] in #523
• docs: explain UHP in the agent protocol ecosystem by @leninworld in #511

New Contributors

• @aswathas made their first contribution in #512
• @leninworld made their first contribution in #511

Full Changelog: v0.35.6...v0.35.7