Cairn

Tool schema required field handling for strict OpenAI backends

NousResearch/hermes-agent · cluster 56123 · agent

Data as of

4 open items. Fix merged in #68154. Check it covers your case.

The short answer

1open issue
3open PRs
21items grouped
Known?
Yes. 21 related items grouped here, 3 issues already closed.
Fix event
A fix was merged to main in PR #68154. Check it covers your case. No release data is tracked.
Tracker
The maintainers' tracker marks this partially resolved, deciding PRs #68154, #112169, #115854. That is separate from the fix event.
Still open
1 issue and 3 PRs.

These issues and fixes concern how the required field in tool/JSON schemas is handled when communicating with strict OpenAI-compatible backends, specifically whether it should be preserved as an empty array, injected when missing, or stripped when null/malformed to avoid HTTP 400 errors. The cluster centers on Moonshot/Kimi and delegate_task schemas, with overlapping but sometimes conflicting approaches to the fix.

Open issues1

  • Issue#60752[Bug]: "Tool schema with required: null causes HTTP 400 on strict OpenAI-compatible backends (e.g. arityflow.top) since v0.11+"

Open PRs3

  • PR#59926fix(delegate): add default=[] to tasks schema for strict OpenAI backends (#59386)
  • PR#60766fix: strip required:null from tool schemas for strict OpenAI-compatible backends
  • PR#61204fix(tools): strip required: null from tool schemas to prevent HTTP 400

Fixes on record

Merged to main. A stamp counts the issues a fix is linked to.

  • #68154 fix(moonshot): inject required:[] on object schemas to fix kimi HTTP 400 (#66835)

    merged to main

    files: agent/moonshot_schema.py, tests/agent/test_moonshot_schema.py, tests/agent/transports/test_chat_completions.py

  • #112169 fix(tools): zero-argument tool schemas keep `required: []` so strict OpenAI-compatible proxies stop 400ing (#111684, #59386, salvage #20151)

    merged to main

    files: contributors/emails/[redacted:email], tests/tools/test_schema_sanitizer.py, tools/schema_sanitizer.py

  • #115854 fix(mcp): MCP tool schemas keep required: [] so strict OpenAI-compatible backends stop rejecting requests (#56123, salvage #106288)

    merged to main

    files: contributors/emails/[redacted:email], tests/tools/test_mcp_tool.py, tests/tools/test_schema_sanitizer.py, tools/mcp_tool_schema.py, tools/schema_sanitizer.py

11 PRs closed without merging

From the close comments: duplicate 3 · merged via another change 3 · superseded by another PR 3 · stale or abandoned 2

  • #56136 fix(tools): preserve empty required array instead of dropping key · superseded by another PR → #20151
  • #59416 fix: drop malformed required schema values · superseded by another PR → bd0affe
  • #59459 fix: keep empty required: [] instead of removing key (#59386) · merged via another change → 40b47b8, #112169
  • #59684 fix(delegate_task): mark tasks parameter nullable for strict OpenAI-compatible backends · stale or abandoned
  • #60702 fix(schema): preserve empty required array in sanitizer and add additionalProperties to delegate_task (#59386) · stale or abandoned
Show 6 more
  • #60755 fix(schema): drop null required from tool schemas · duplicate → #59416, #29329, #59421, #60752
  • #66849 fix(tools): keep empty required array instead of stripping it · merged via another change
  • #66853 fix(moonshot): ensure required array is always present in tool schemas · duplicate → #66852
  • #66855 fix(agent): inject empty required array on Moonshot object schemas (#66835) · merged via another change → #68154
  • #67430 fix(moonshot): inject required: [] on object schemas missing it · superseded by another PR → #68154, #66855, #66852
  • #71220 fix(tools): keep empty required[] instead of dropping the key (#59386) · duplicate → #59459
Closed issues · 3
  • Closed#56123fix: schema_sanitizer strips required field causing HTTP 400 on strict OpenAI-compatible backends
  • Closed#59386[Bug]: `delegate_task` schema causes HTTP 400 / non-retryable crash on strict OpenAI-compatible backends
  • Closed#66835Moonshot/Kimi: tool schemas with empty properties missing "required" array cause HTTP 400
How this cluster was grouped
  • Link evidence (partly structural links): some members are connected by structural evidence (shared changed files, or a closing/superseded reference); the rest are joined by an automated relevance judgement over their text.
  • Members outside that structural core may belong to a different underlying problem.
  • Pairwise link density 0.09: the share of item pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. 1.00 means every pair is linked.

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At a glance

Subsystem
agent
Merged PRs
#68154, #112169, #115854
Closed issues
3
Attempts
11 PRs closed without merging
Fix link checked
19 Sep 2026

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