[diegosouzapw]

Summary

• The thinking-model reasoning_content placeholder injector (OpenCode thinking models, Kimi/Moonshot and requiresReasoningContentEcho registry entries) only treated a string reasoning_content as present. An assistant message carrying the reasoning alias, or an array-valued carrier, got a second reasoning_content, and serde-based upstreams (DeepSeek, Kimi, GLM) reject that body with 400 duplicate field reasoning_content.
• The injector now skips any assistant message with a non-empty (trimmed) string or a non-empty array in either reasoning_content or reasoning. Messages with no carrier still get the placeholder (unsupported_country_region_territory (bug?) #1543 contract kept).
• Narrow delta only: the translator half (folding reasoning into reasoning_content on replay turns) already landed in fix(sse): drop reasoning alias once reasoning_content carries the replay #16646. The injector does not rename or delete the alias.

Attribution

Thanks to @AppleVibe for the original implementation.

Changes

• open-sse/utils/reasoningContentInjector.ts: hasNonEmptyReasoningContent → hasAnyReasoningCarrier (string or array, reasoning_content or reasoning; strings keep the .trim() semantics).
• tests/unit/reasoningContentInjector.test.ts: 6 new cases (alias-only, both carriers, array reasoning_content, array reasoning, no carrier, whitespace/empty carriers still injected).
• reasoning_details (OpenRouter shape) deliberately not counted as a carrier, same as the original fix; no test needs it.

Test plan

• TDD, before the fix: node --import tsx/esm --test tests/unit/reasoningContentInjector.test.ts → ℹ tests 11 ℹ pass 8 ℹ fail 3 (alias-only, array reasoning_content, array reasoning). After: ℹ tests 11 ℹ pass 11 ℹ fail 0.
• Every unit test file citing reasoningContentInjector or reasoning_content (150 files, test:unit:ci preamble, concurrency 4): ℹ tests 2207 ℹ pass 2195 ℹ fail 12. All 12 failures were in tests/unit/deepseek-web.test.ts (10 s AbortSignal.timeout on PoW under load average ~17; this executor does not import the injector). Rerun alone at lower load: ℹ tests 35 ℹ pass 35 ℹ fail 0.
• Integration files citing the symbols (7 files, concurrency 1): ℹ tests 26 ℹ pass 8 ℹ fail 0 ℹ skipped 18 (live/e2e suites skip without credentials).
• npx eslint --suppressions-location config/quality/eslint-suppressions.json <changed files> → exit 0; npx prettier --check <changed files> → clean.
• npm run typecheck:core → exit 0.
• GITHUB_BASE_REF=release/v3.8.53 node scripts/check/check-pr-test-policy.mjs → Result: PASS; GITHUB_BASE_REF=release/v3.8.53 npm run check:test-masking → OK — 1 modificado(s) … sem enfraquecimento.