Project Adapters

Adapters

Mental Model

An adapter is a sealed unit that converts one source format into the canonical event stream. It knows everything about its format and nothing about anything else. See .agents/sow/specs/adapter-contract.md.

Adding a New Adapter

1. Read the format authoritatively first. Open the upstream source mirror under /opt/baddisk/monitoring/repos/ai/<tool>/ and read its persistence code. Sample real files (sanitized) from the operator's environment.

2. Write the spec first. Create .agents/sow/specs/adapter-<name>.md. Required sections: source format, record shape, watch strategy, cursor design, mapping to canonical events, sub-agent linkage, known edge cases, references. The spec is the source of truth; the code follows.

3. Create the package. internal/adapters/<name>/adapter.go. Implement the canonical.Adapter interface. Keep the file under 400 lines; split helpers into sibling files.

4. Commit sanitized fixtures. testdata/<name>/<scenario>/. Scenarios are listed in testing-strategy.md. Run scripts/sanitize-fixture.sh before committing.

5. Write tests. Scan, Tail, cursor resume, error handling, idempotency. Use golden files.

6. Register the factory. internal/adapters/registry.go:

   registry["myadapter"] = myadapter.Factory
   

7. Add auto-discovery probe. internal/ingest/discover.go: add a probe entry that detects the format's presence on disk.

8. Update docs. README.md Source Formats table; docs/adding-an-adapter.md if any new patterns emerged.

9. Open or update a SOW. Use the external reviewer gates from project-second-opinions on the adapter SOW's gap analysis, implementation plan, and implementation before closing the work.

Modifying an Existing Adapter

1. Read the adapter's spec under .agents/sow/specs/adapter-<name>.md.
2. Read recent commits to that adapter (git log -p internal/adapters/<name>/).
3. Check existing fixtures for coverage of the case you're touching.
4. Make the change.
5. Update the spec in the same commit as the code.
6. Run go test ./internal/adapters/<name>/... with -race.
7. If the canonical mapping changed, refresh golden files with -update-golden and inspect the diff manually before committing.

Common Pitfalls

• Closing the out channel. Don't. The ingester owns it.
• Panicking on bad input. Don't. Call opts.OnError and continue.
• Re-emitting on every Scan call. Use the cursor; the ingester does dedup but adapter-side dedup is far cheaper.
• Forgetting to Add new subdirs. fsnotify in Go is not recursive; you must Add each subdirectory.
• Reading symlinks outside the configured root. Resolve with filepath.EvalSymlinks and verify the result is inside the root.
• Holding files open across goroutine boundaries. Open, read, close in one goroutine.

Cursor Design Tips

• A cursor must be persistable and resumable. Don't store live channels or file handles.
• Idempotent on replay: scanning twice with the same cursor should produce the same events.
• Survive source rewrites: if the source overwrites a file, the cursor must detect it (mtime + size + content hash where appropriate).

Sub-Agent Linkage

The canonical model expresses sub-agents as SessionStartedEvent with ParentNativeID set. The adapter is responsible for figuring out parent/child relationships from the source format and emitting that field correctly. The ingester does the cross-session resolution; the adapter just provides the native IDs.

Validation Checklist

Before marking adapter work complete:

• Spec under .agents/sow/specs/adapter-<name>.md matches the implementation.
• Fixtures cover happy/multi-turn/sub-agents/tools/failures/in-progress/cursor-resume.
• Golden files reviewed manually.
• go test -race ./internal/adapters/<name>/... passes.
• golangci-lint run ./internal/adapters/<name>/... clean.
• Auto-discovery probe added.
• README Source Formats table updated.
• Applicable external reviewer gates from project-second-opinions converged for the adapter SOW or substantial milestone.