refactor(usage): OpenCode usage comes from provider-opencode

[juliusmarminge]

The OpenCode usage reader and its OPENCODE_DATA_DIR/XDG root resolution lived in apps/server.

They move into provider-opencode as a scan reader on OpenCodeDriver.usage. UsageService runs scan readers generically and fills in a source's volume id from its directory when a reader leaves it out. Tests move with the code.

🤖 Generated with Claude Code (Claude Opus 5.5, Claude Code harness)

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

ℹ️ No successful main baseline artifact is available yet. This run establishes the initial measurement.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	—	5.0 KiB	—	6.8 KiB	✅
Codex	Thread snapshot wire	—	3.8 KiB	—	4.9 KiB	✅
Codex	Live turn WebSocket wire	—	1.2 KiB	—	2.0 KiB	✅
Codex	Live turn WebSocket decoded	—	20.9 KiB	—	29.3 KiB	✅
Codex	Live turn messages	—	2	—	8	✅
Claude	Total thread wire	—	5.0 KiB	—	6.8 KiB	✅
Claude	Thread snapshot wire	—	3.8 KiB	—	4.9 KiB	✅
Claude	Live turn WebSocket wire	—	1.2 KiB	—	2.0 KiB	✅
Claude	Live turn WebSocket decoded	—	21.2 KiB	—	29.3 KiB	✅
Claude	Live turn messages	—	1	—	8	✅

Baseline: unavailable · PR result: 0d411e3 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This is primarily a behavior-preserving refactor that relocates OpenCode usage scanning into its provider package and adds generic scan plumbing. The new test file also adds a file-level static-analysis suppression directive, requiring human review.

No code changes detected at 0d411e3. Prior analysis still applies.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

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• Run ID: 1d3ba86e-6648-4465-97a6-8dfd3ffc9294

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📥 Commits

Reviewing files that changed from the base of the PR and between a973909 and 0d411e3.

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📒 Files selected for processing (2)

• apps/server/src/usage/UsageService.ts
• packages/provider-core/src/server/usage.ts

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📝 Walkthrough

Walkthrough

OpenCode usage history is now read through a provider scan reader registered as a built-in usage driver. UsageService runs built-in scan readers alongside its other usage sources. The scan result contract allows readers to omit a volume ID.

Changes

OpenCode usage scanning

Layer / File(s)	Summary
OpenCode scan reader and contract packages/provider-core/src/server/usage.ts, packages/provider-opencode/src/server/usage.ts, packages/provider-opencode/src/server/usage.test.ts, apps/server/src/usage/usageTranscriptReader.test.ts	The scan contract makes volumeId optional. The OpenCode reader resolves and deduplicates data roots, scans them, and reports missing or partially readable history. Tests for SQLite and legacy JSON history are now in the OpenCode package; the corresponding test was removed from the server transcript-reader suite.
Register OpenCode scan reader packages/provider-opencode/src/server/driver.ts, apps/server/src/provider/builtInDrivers.ts	OpenCodeDriver exposes openCodeUsageReader and is included in the built-in usage driver list.
Run scan readers during usage collection apps/server/src/usage/UsageService.ts	UsageService selects built-in scan readers, supplies configured instances and scan cutoffs, normalizes returned sources, and includes them in collection. The dedicated OpenCode collection path was removed.

Priority: ⬇️ Low

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

Change: Refactor

Sequence Diagram(s)

sequenceDiagram
  participant UsageService
  participant OpenCodeDriver
  participant openCodeUsageReader
  participant FileSystem
  UsageService->>OpenCodeDriver: select built-in scan reader
  UsageService->>openCodeUsageReader: provide instances and scan cutoffs
  openCodeUsageReader->>FileSystem: resolve roots and read usage history
  FileSystem-->>openCodeUsageReader: history results
  openCodeUsageReader-->>UsageService: scanned sources and status

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Suggested reviewers: t3dotgg

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Merge Risk: ⚪ Minimal · up to 0d411

No actionable OpenCode usage regression was established; this PR is mergeable after normal checks.

Pre-merge checks | 3 | 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check		The description explains the code movement and generic scan-reader change, but it omits the required Problem, Scope and approval, and Verification sections. It provides no test results or statement of…	Add the required Problem, Change, Scope and approval, and Verification sections. Include the problem and expected behavior, issue or maintainer approval details, focused tests with observed results, and any checks that were not run.

✅ Passed checks (3 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.
Title check		The title clearly identifies the main change: moving OpenCode usage handling into provider-opencode. It is concise and specific.

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Full details: Description check

Explanation

The description explains the code movement and generic scan-reader change, but it omits the required Problem, Scope and approval, and Verification sections. It provides no test results or statement of unchecked items.

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