fix(loops): meter the usage an adapter error terminal carries

[vadymhimself]

Depends on #7179. This branch is built on #7179's head (fix/web-search-loop-iteration-usage), so the diff includes #7179's three commits until it lands. This PR's own change is the single commit fix(loops): meter the usage an adapter error terminal carries (84e7728). I will rebase once #7179 merges.

Summary

• A web-search or image-bridge pass that ends in an adapter error event was still billed by the provider (for example a pass that generated output and then hit a provider error). parseStreamWithProgress (src/web-search/progress-stream.ts) fails the stream as soon as it sees that event, so the usage the event carries never reached either loop. The errored pass looked free in the request log.
• parseStreamWithProgress now takes an optional onErrorUsage callback and hands it the error event's usage before failing. Nothing else in progress-stream changes: the stream still fails with the same error at the same point.
• src/web-search/loop.ts adds that usage to fix(web-search): meter every sidecar iteration in the usage ledger, not only the last #7179's hiddenUsage, which the existing in-stream error path already reports through deps.onUsage. Ledger only, as in fix(web-search): meter every sidecar iteration in the usage ledger, not only the last #7179: the client's response.failed carries no usage, the same as before.
• src/images/loop.ts adds it to its own hiddenUsage with the existing addUsage, on both the parseStream path and the runTurn error branch. The image loop already puts hiddenUsage on the error event it yields, so the bridge reports it through onUsage and on response.failed.usage. That number now includes the errored pass too.
• Error semantics are unchanged in both loops: same LoopError, same status, same message (Provider stream error: ...). No sidecar search or media call runs after an adapter error.
• structure/runtime.md (the web-search loop paragraph fix(web-search): meter every sidecar iteration in the usage ledger, not only the last #7179 extends) documents the rule.
• Out of scope, unchanged: the image loop's private addUsage is not swapped for the shared mergeUsage. src/web-search/run-turn-loop.ts already passes the error event through to the bridge with its usage.

Verification

• New tests/web-search/web-search-loop-error-usage.test.ts (1 case): a search pass (1000/50) followed by a pass that streams text and then errors with usage 1400/30. It asserts the turn still fails with Provider stream error: provider blew up and that onUsage receives 2400/80.
• tests/images/loop.test.ts: 2 new cases (parseStream through the real progress stream, and runTurn). Each is an image-call pass (10/4) followed by an errored pass (3/2), and asserts onUsage receives 13/6.
• Red on upstream/dev (60bf4c7e0): web-search 0 pass / 1 fail, where the ledger received nothing ([]). Images 0 pass / 2 fail, where the ledger received 10/4.
• Red on fix(web-search): meter every sidecar iteration in the usage ledger, not only the last #7179's head (d97f86a3e): web-search ledger received 1000/50 and dropped the errored pass. Images: 10/4.
• Green on this branch: 3 pass / 0 fail.
• bun test tests/images/loop.test.ts tests/web-search/: 431 pass / 0 fail across 23 files.
• bun run typecheck: clean. bun run structure:check: passed. bun scripts/file-size-ratchet.ts: passed. bun run privacy:scan: passed. Layout guards (tests/test-layout.test.ts, tests/test-layout-tooling.test.ts): pass.
• bun run test:changed (Bun 1.4.3): 14857 pass / 35 skip / 1 fail across 596 files. The one failure is connected-client runtime probe scope > a rejected preferred runtime falls back without rewriting the saved selection. It fails the same way on a clean upstream/dev checkout and is unrelated to this change.
• I did not run the full bun run test suite locally. CI covers it.

Checklist

• Scope stays focused and avoids unrelated cleanup.
• Docs or release notes were updated when needed.
• Security-sensitive changes were reviewed for secrets, auth, and unsafe defaults.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Usage reports now include token and cache usage from earlier search and image-generation iterations, including iterations that are retried or end in an error.
  • When a search request fails, usage from completed and failed iterations is still reported.
  • The final response continues to show usage and context details from its final iteration.

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[vadymhimself]

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📝 Walkthrough

The image and web-search loops now include usage from hidden iterations and errored adapter passes in usage reporting. Web-search client terminal usage remains tied to the final iteration; hidden context totals and raw usage are excluded. Tests, test-layout mappings, and runtime documentation cover these behaviors.

Changes: Loop usage reporting

Layer / File(s)	Summary
Capture usage from adapter errors src/web-search/progress-stream.ts, src/images/loop.ts, tests/images/loop.test.ts	The progress-stream parser forwards usage attached to adapter error events. Image-loop paths add error-pass usage to hidden usage, with tests checking the surfaced error and combined totals.
Aggregate web-search iteration usage src/web-search/loop.ts, tests/web-search/*, scripts/test-layout/layout.json, tests/fixtures/test-layout-expected.json, structure/runtime.md	The web-search loop reports usage from hidden iterations and error paths. Final client-facing usage remains from the final iteration, and hidden context totals and raw usage are excluded. Tests, test-layout mappings, and runtime documentation cover these rules.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Suggested reviewers: lidge-jun

Merge Risk: ⚪ Minimal · up to 84e77

The change makes request-log usage include billed adapter-error passes without altering error behavior. No concrete merge-blocking risk was found.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 60.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 6 files. (3 skipped: 3…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly identifies the main change: reporting usage carried by adapter error terminals in loop processing. It is concise, specific, and directly matches the pull request objectives.

Full details: Docstring Coverage

Explanation

Docstring coverage is 60.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 6 files. (3 skipped: 3 unsupported.)

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Actionable comments posted: 1

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• 🪄 Fix comments: Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at @structure/runtime.md:
- Line 401: Split the usage-accounting contract in the runtime documentation
into its own heading, covering hidden-iteration usage, onUsage and onErrorUsage
reporting, and the client-facing terminal’s usage. Keep the search-budget,
recovery, run-turn-loop, and result-formatting rules in their appropriate
sections, preserving the documented behavior in the present tense.

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📥 Commits

Reviewing files that changed from the base of the PR and between 60bf4c7 and 84e7728.

📒 Files selected for processing: 9

• scripts/test-layout/layout.json
• src/images/loop.ts
• src/web-search/loop.ts
• src/web-search/progress-stream.ts
• structure/runtime.md
• tests/fixtures/test-layout-expected.json
• tests/images/loop.test.ts
• tests/web-search/web-search-loop-error-usage.test.ts
• tests/web-search/web-search-loop-iteration-usage.test.ts

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[lidge-jun]

Being carried into #7225 with your authorship preserved; this PR will be closed when the bundle lands.

[lidge-jun]

Landed on dev in 300e426 via #7225 (your change is its own commit in that bundle, and the squash keeps your authorship as Co-authored-by). Thank you!