{"repo":"NousResearch/hermes-agent","public_id":"89886","display_label":"Prompt caching cache_control on tool results causes 400 errors","summary":"These items concern a bug where cache_control fields on tool_result content arrays trigger non-retryable 400 errors from Anthropic-format APIs, breaking tool-using sessions. The members include a version report and two related fix attempts targeting LiteLLM Anthropic proxy configurations.","subsystem":"agent","counts":{"members":3,"open_issues":0,"open_issues_distinct":0,"open_prs":0,"closed_issues":1,"merged_prs":1,"attempt_prs":1},"landed_fix":{"status":"merged_to_main","basis":"structural","pr":97710,"merged_at":"2026-08-29T06:36:49+00:00"},"resolution":{"state":"resolved","by":"pr-97710"},"freshness":{"state":"verified","last_verified_at":"2026-08-29T06:36:49+00:00","is_stale":false},"grouping":{"backbone":"STRUCTURAL_SPANNING","link_density":0.6666666666666666},"fix_edges":[{"issue_number":89886,"pr_number":97710,"tier":"verified","basis":"closing_ref","confidence":0.95,"recoverable_from_timeline":true,"pr_merged_at":"2026-08-29T06:36:49+00:00"}],"members":[{"kind":"issue","number":89886,"title":"v2026.8.18: cache_control on tool_result.content[] rejected by Anthropic-format API (non-retryable 400, kills any tool-using session)","url":null,"state":"closed"},{"kind":"pr","number":89931,"title":"fix(prompt-caching): tool-using sessions no longer 400 behind LiteLLM Anthropic proxies (#89886)","url":null,"state":"closed","close_reason":{"refs":[{"kind":"commit","value":"1d8946b40b","number":0},{"kind":"pr","value":"#97710","number":97710},{"kind":"pr","value":"#90971","number":90971}],"category":"merged_via","implication":"superseded"},"merged":false},{"kind":"pr","number":97710,"title":"fix(prompt-caching): tool-using sessions no longer 400 behind LiteLLM Anthropic proxies (salvage of #89931)","url":null,"state":"merged","close_reason":{"category":"merged"},"merged":true,"is_fix_pr":true,"fix_tier":"verified","files_changed":["agent/agent_runtime_helpers.py","agent/conversation_loop.py","agent/moa_loop.py","agent/prompt_caching.py","tests/agent/test_litellm_tool_part_cache_markers.py"]}],"trust":{"default_tier":"verified","includes_suggested":false}}