Clarify when HttpClient transport errors need translation

[Wenjie Fan (gggdttt)]

Summary

Clarify the existing HTTP platform-failure article without changing its fail-fast alternative:

• Both omitted optional Boolean/runtime propagation and explicit Boolean handling can be valid. Require visible caller, documented error-contract, or concrete user-facing evidence before reporting missing custom transport-error translation.
• A custom error or label for completed non-2xx responses does not itself establish a transport-error translation requirement. Preserve genuine consumed-false success conversion and non-success response/body defects.

One article changed, four inserted lines. Existing good/bad samples and fixture selection remain unchanged. No engine, general skill, schema, pin, gold, or evidence changes. This is a separate change from #220 and merged #196, based on 86d809b5252aa2fe187ccb9f16bef435bb8c9be6 (live main verified before editing).

Evidence and scope

Motivated by the sealed read-only diagnosis of BC-Bench run 37616085214, under recall-closure work item 649781:

• Bench e15e5adbc31754e222b9d2e97057fe9c8c2fb9f6 -> engine 0b01ed8c90f3b07cbc693aa8869f84a16ded338d -> BCQuality 8c9385c16fdb1f21afa6ce957420ead73294d06d.
• The optional-clean root emitted two unsupported custom-message findings at bare GET line 10 / POST line 22; all 19 leaves were silent. The findings acknowledged platform runtime failure, rather than claiming silent success. The supplied source has non-2xx status handling but no caller/error-translation contract establishing why runtime propagation is insufficient.
• The run had six artifact-valid/scored entries and one cancellation-incomplete entry; 139 completed reviewer records had no observed original schema/semantic generation failures. This is not a 7/7 success or a causal-fix claim.
• Sealed diagnosis SHA-256: 15220504938d7d558a662a736eec515bb6fdd28c04c131083a5c04d3abea6561; evidence index: c7b382a69fef893e8fb8ffd2fca70458d315f6190ce2ec7c820b8113ef1653ca. Both were verified before editing; evidence was not rewritten.

Local validation before publishing

• python -X utf8 .github\scripts\validate_frontmatter.py --root .: passed, 0 errors, 2 existing unrelated keyword-count warnings. An initial Windows cp1252 stdout encoding failure was resolved by rerunning the unchanged validator with UTF-8 output.
• pwsh -NoProfile -File .github\scripts\Test-KnowledgeIndex.ps1 -Root .: passed, 414 articles, deterministic/full index coverage; bounded retrieval round-tripped 414 articles and 715 samples. Existing HTTP source-contract and exact-body reachability checks passed.
• pwsh -NoProfile -File tools\Test-ReviewFixtures.ps1 -Root . -ChangedPathsFile <session-files>\http-translation-changed-paths.txt -CoverageReportPath <session-files>\http-translation-coverage.json -PrepareDirectory <session-files>\http-translation-prepared: passed, 252 cases covering 126/346 paired articles across 20 domains; changed-article coverage passed without a waiver. Existing report-contract checks passed (8 predicate cases plus executable acceptance cases). This only prepared inputs; it did not invoke a model.
• git diff --check: passed; inspected one-file, four-line diff.

The existing fixture convention already selects the HTTP good/bad pair. No string-presence tests were added as a proxy for model behavior. Manual normative review covered bare GET/POST with status handling, label present/absent neutrality, explicit caller translation contracts (violated and satisfied), consumed-false defects, non-2xx success parsing, swallowed TryFunction diagnostics, and contextual recoverable-error guidance. The detailed scenario matrix and exact patch are retained in the implementation session handoff, outside the repository.

Limitations

Offline validation proves content/fixture integrity and helper-level exact-body reachability, not actual root/leaf retrieval, correct model silence, precision/recall, or causal correction. The retrieval/evidence-transfer hypothesis remains unproven; the clarification may be redundant with existing fail-fast and precision rules. No fresh live smoke, reviewer/judge invocation, or workflow dispatch was performed. No change to general error-handling guidance or blanket suppression of root findings is intended.

[Jesper Schulz-Wedde (JesperSchulz)]

Reviewed draft head cc5c60f37a70963d96aa18ccf1b3fe405bd56146. The clarification is sound: omitting HttpClient's optional Boolean propagates transport/platform errors, and a custom non-2xx response message does not establish a separate obligation to translate transport failures. The text preserves explicit caller/error-contract requirements and continues to reject consumed-false success conversion or response processing after transport failure. Existing canonical fixtures and deterministic registration are unchanged. Exact-head local frontmatter, changed-path fixture preparation (252 cases), review-contract, skill/schema and index/retrieval checks pass; all reported GitHub checks are green. No merge-critical issue found; content is ready when the draft is marked ready for review.