fix(routing): health evidence counts physical sends and final terminal

[vadymhimself]

Summary

Policy-route health (src/routing/health.ts) mis-scored two kinds of request-history rows:

• Mid-stream abort after a failover counted as success. attemptSamplesFor expands multi-attempt rows into per-attempt samples but hard-coded closeReason: null / terminalStatus: null. When a combo failed over to a target that returned 200 and then had its stream cut (row terminalStatus: "incomplete", final attempt status: 200, streamAborted: true), that target got a success sample. Routing kept favouring a target that drops streams; each drop is a paid partial generation plus a client retry.
• Rows with no physical send counted as evidence. A request answered locally (locallyAnswered) or refused before it left the proxy (sendCount: 0) still produced a sample: a single-attempt row fell back to the row itself, and a non-sent attempt inside a combo row contributed its status (for example a 503 against a target that never received the request).

Fix: the row's terminal status and close reason are applied to its last physical send, and attempts or rows with no physical send contribute no sample. attemptSamplesFor now returns undefined when the row itself is the sample and [] when the row sent nothing upstream. Single-attempt rows with a physical send still use the row, so their latency and terminal semantics do not change.

Out of scope: single-attempt combo rows (attempt_count = 1, top-level provider combo) are still not expanded into evidence, and there is no rowid tiebreak for equal-timestamp samples. I left both out because I could not build a failing behaviour test for either within this change.

Verification

• Red on dev (60bf4c7): bun test tests/server/health-scoring.test.ts returned 13 pass, 2 fail. The abort test got failures undefined (expected 1), and the no-send test got sampleCount 7 (expected 5).
• Green with the fix: 15 pass, 0 fail.
• bun run typecheck: clean.
• bun run structure:check: passed. The doc sentence is in structure/dashboard-and-usage.md, next to the existing note on how health scoring reads the history index. catalog.md is at its 600-line budget.
• tests/lab/core-lab-boundary.test.ts and tests/test-layout.test.ts: pass. The change adds no imports.
• bun run test:changed (Bun 1.4.3): 29952 pass, 10 fail. I re-ran the 4 failing files in isolation on this branch and on a clean dev worktree, and both give the same result: 278 pass, 1 fail. The one failure is connected-client runtime probe scope > a rejected preferred runtime falls back without rewriting the saved selection, and it fails on dev too. The other 9 (live audio readiness timeouts, service SQLite-home/diagnostics) pass in isolation, so they look like load flakes in the full parallel run.
• I did not run the full bun run test; 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
  • Health scores now reflect requests that were physically sent to a provider. Requests answered locally or refused before sending no longer contribute evidence for a provider.
  • When a stream is interrupted after returning a successful HTTP response, the resulting failure is attributed to the provider that streamed it. Successful fallback attempts are counted for the provider that handled them.
• Documentation
  • Updated request-history guidance to explain how physical sends and terminal outcomes affect health scoring.

Review readiness checklist

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[vadymhimself]

@coderabbitai review

[coderabbitai]

📝 Walkthrough

Health scoring now counts physical upstream sends as attempt samples. Attempts answered locally or refused before sending do not provide target evidence. Terminal outcomes apply to the last physical send.

Changes: Physical-send health scoring

Layer / File(s)	Summary
Select and score physical sends src/routing/health.ts:97–145, 259–289, tests/server/health-scoring.test.ts:250–292, structure/dashboard-and-usage.md:282	attemptSamplesFor distinguishes rows that need row-level fallback from rows with no upstream send. It filters out locally answered and zero-send attempts, and assigns terminal outcome fields to the last physical send. The query no longer selects attempt_count. Tests cover incomplete streams and zero-send attempts. The request-history documentation describes these scoring rules.

Priority: ⬇️ Low

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

Change: Bug fix

Suggested reviewers: lidge-jun

Merge Risk: 🔵 Low · up to b211a

Health scoring now ignores attempts that never reached a provider and charges a stream failure to the target that dropped it. One gap remains: requests refused before any attempt was recorded can still affect a target's health score. The impact is bounded, but the gap should be closed with a small guard.

Pre-merge checks: 5

Check name	Status	Explanation
Docstring Coverage		Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 2 files. (1 skipped: 1 …
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 summarizes the main change: health evidence now counts physical sends and preserves the final terminal outcome for the last physical send.

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Actionable comments posted: 1

---

• 🪄 Fix comments: Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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Inline comments:
Review comments at @src/routing/health.ts:
- Line 120: Update attemptSamplesFor so rows without an attempts array return no
provider-health samples when localTerminalReason is a string, while preserving
the existing undefined fallback for other rows. Parse and inspect the existing
localTerminalReason marker before the main-row fallback; leave rows with an
attempts array unchanged.

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ℹ️ Review info

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• Configuration used: Repository: lidge-jun/opencodex/.coderabbit.yaml
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📥 Commits

Reviewing files that changed from the base of the PR and between 60bf4c7 and b211ae4.

📒 Files selected for processing: 3

• src/routing/health.ts
• structure/dashboard-and-usage.md
• tests/server/health-scoring.test.ts

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Review readiness checklist

• ⬜ Required local validation passed; commands, results, and any full-suite exception are documented.
• ⬜ I pushed my PR to a recent dev commit (at most 10 behind; a maintainer may still ask for the exact tip before merge).
• ⬜ I resolved all correct Codex and CodeRabbit findings.
• ⬜ My PR is ready for review.

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[lidge-jun]

Being carried into #7224 with your authorship preserved; this PR will be closed when the bundle lands.

[lidge-jun]

Landed on dev in 6ccb47a via #7224 (your change is its own commit in that bundle, and the squash keeps your authorship as Co-authored-by). Thank you!