fix(sse): dynamically inject skills beta only when code_execution tool is present (#14200)

[HouMinXi]

fix(sse): dynamically inject skills beta only when code_execution tool is present (#14200)

Summary

Fixes #14200.

skills-2025-10-02 beta was previously statically declared in ANTHROPIC_BETA_BASE, which caused upstream Anthropic to reject all tool-less requests (such as plain text completions) with HTTP 400:

[400]: Skills beta requires the code_execution tool to be included in the request.

This PR moves skills-2025-10-02 out of the static beta lists and injects it dynamically only when a code_execution tool is detected in the request body. It also strips the beta if forwarded by client headers when the request contains no code_execution tool.

⚠️ base-red inherited: #13866

Changes

• open-sse/config/anthropicHeaders.ts:
  • Removed skills-2025-10-02 from ANTHROPIC_BETA_BASE, ANTHROPIC_BETA_API_KEY, and ANTHROPIC_BETA_CLAUDE_OAUTH.
  • Added hasCodeExecutionTool(body) helper to detect code_execution_20250825, code_execution tool types or functions.
  • Added maybeAppendSkillsBeta(headers, provider, body, extraCondition) to dynamically append skills-2025-10-02 when appropriate for Anthropic family providers.
  • Added syncSkillsBeta(headers, provider, body, extraCondition) and removeAnthropicBetaHeader(headers, token) to synchronize the header with the finalized request body.
  • Updated mergeClientAnthropicBeta(headers, clientBeta, model, body) to drop skills-2025-10-02 when client attempts to negotiate it on tool-less requests.
• open-sse/executors/base.ts:
  • buildHeaders: dynamically evaluates skills beta on initial headers.
  • execute: invokes syncSkillsBeta on transformedBody after transformRequest() to guarantee headers stay in sync with the body actually sent upstream.
• open-sse/executors/default.ts:
  • Passed body into buildHeaders.
• open-sse/services/provider.ts:
  • Added dynamic skills beta gating to both the CC-compatible early exit and the main header path.
• open-sse/services/claudeCodeCompatible.ts:
  • Re-exported new header helpers.
• tests/unit/issue-14200-anthropic-skills-beta-toolless.test.ts:
  • Added test suite covering tool-less requests, tool requests, client header filtering, CC-compatible providers, and null/undefined body safety.

Verification

• npm run typecheck:core: 0 errors
• npm run check:cycles: 0 cycles
• node --test-force-exit --import tsx/esm --test tests/unit/issue-14200-anthropic-skills-beta-toolless.test.ts ...: 34/34 passed

[diegosouzapw]

This is a P0 fix — every tool-less request on the API-key Anthropic path is 400ing on the current tip right now, and I confirmed it directly (skills-2025-10-02 is still unconditional in ANTHROPIC_BETA_BASE). Your fix threading maybeAppendSkillsBeta/syncSkillsBeta through base.ts, default.ts, provider.ts and the CC-compatible path, plus re-syncing after transformRequest reshapes the body, is thorough — that's the part a narrower fix would have missed. Ran both your new suite and the existing #9064 regression guard locally: 13/13 pass. Merging.

For the record: the same gate was first proposed in #10651 (@dpozimski, August) and closed by its author before merging; we'll add a courtesy Co-authored-by trailer at squash. Also worth stating in the PR body that the Claude OAuth / Claude-Code-protocol path was never affected (selectBetaFlags() replaces the header there) — only the API-key path sent the beta unconditionally.