Skip to content

copilot.md

Latest commit

 

History

History
69 lines (47 loc) · 3.39 KB

copilot.md

File metadata and controls

69 lines (47 loc) · 3.39 KB

Copilot

GitHub Copilot Chat (CLI and VS Code extension transcripts).

  • Source: src/providers/copilot.ts
  • Loading: eager (src/providers/index.ts:3)
  • Test: tests/providers/copilot.test.ts (401 lines)

Where it reads from

Two JSONL locations plus an optional OpenTelemetry SQLite source (see below). All discovered sources are walked on every run; results merge and dedupe.

  1. Legacy CLI sessions: ~/.copilot/session-state/
  2. VS Code transcripts: ~/Library/Application Support/Code/User/workspaceStorage/<hash>/GitHub.copilot-chat/transcripts/ and equivalents on Windows / Linux
  3. OTel SQLite store: VS Code Copilot Chat's agent-traces.db (see the OTel section). Preferred when present because it carries full input / output / cache token counts; the JSONL sources only record output tokens.

Storage format

JSONL in the first two locations (schemas differ; the parser switches by detecting which schema the first event uses), and a SQLite DB for the OTel source.

OpenTelemetry (OTel) source

When VS Code Copilot Chat's agent-traces.db exists, the parser reads per-LLM-call token breakdowns (input, output, cache-read, cache-creation) from it, which the JSONL sources do not record. Discovery is skipped with CODEBURN_COPILOT_DISABLE_OTEL=1, and the DB path can be overridden with CODEBURN_COPILOT_OTEL_DB.

  • Requires Node 22+. The OTel source uses the built-in node:sqlite module (the same backend as Cursor / OpenCode). On Node 20, or if the DB is missing / locked / corrupt / wrong-schema, OTel is skipped and the JSONL/transcript sources are used as a fallback.
  • Durable cache (monotonic totals). Copilot is marked durableSources: OTel-derived cache entries are never evicted when VS Code prunes old spans from the DB, so month-to-date totals do not drop as the DB rotates. Entries age out after 90 days.
  • Upgrade note. The first run after upgrading to the OTel version bumps the copilot parse version, which discards the prior copilot cache. Spans already pruned from the DB before the upgrade cannot be recovered, so monotonicity starts from the upgrade point, not retroactively.

Caching

None for the JSONL sources. The OTel source uses a durable cache (see above).

Deduplication

Per messageId in both formats (copilot.ts:118 for legacy, copilot.ts:245 for transcripts).

Model inference

Copilot does not always tag the model on each message. The parser infers it from the tool-call ID prefix:

Prefix Inferred model family
toolu_bdrk_, toolu_vrtx_, tooluse_, toolu_ Anthropic
call_ OpenAI

See copilot.ts:176-213.

Quirks

  • toolRequests can be missing or non-array on older sessions; the parser guards against that (copilot.ts:126, :260).
  • When outputTokens is missing the parser falls back to char-counting (CHARS_PER_TOKEN = 4, copilot.ts:252-254).
  • A single chat may be mirrored across both legacy and transcript paths if the user upgraded; the dedup messageId collision handles this.

When fixing a bug here

  1. Determine which schema reproduces the bug. The two parsers share little code on purpose; do not unify them unless you understand both formats.
  2. If the model is misidentified, look at the tool-call ID prefix list and consider whether a new prefix should be added.
  3. New fixtures go under tests/fixtures/copilot/ and are referenced from tests/providers/copilot.test.ts.