JetBrains Copilot plugin ≤1.5.x (e.g. 1.5.59-243) stores all session turns
inside ONE large binary-framed outer Nitrite document, rather than the
per-turn {"__first__":{"type":"Subgraph",...}} blobs introduced in later
plugins (≥1.12.x, e.g. 1.12.1-251).
In the old format each assistant turn is a UUID-keyed Value entry whose
value field contains a JSON-string-escaped AgentRound record:
{"<uuid>":{"type":"Value","value":"{\"type\":\"AgentRound\",
\"data\":\"{...reply...}\"}"}, ...}
The extractResponseText depth-unescape loop already handles this one extra
level of escaping; the only gap was that extractJetBrainsDbTurns never fed
it the outer document — it only scanned for __first__/Subgraph blobs, which
the old plugin never writes.
Add a fallback that activates when the Subgraph scan produces zero turns but
'AgentRound' text is present in the raw file (old-format signal). It locates
the binary-framed outer document (UUID-keyed Value entry, hex matched
case-insensitively so an uppercase UUID does not fall through to $0), extracts
it with matchJsonObject, and passes it to extractResponseText. Because the outer
document holds every turn in one blob, this emits ONE session-level call per
document (all rounds' replies joined): cost/tokens are correct, only the
per-turn call-count granularity is coarser — an accepted tradeoff for legacy
data. MVStore keeps two identical collection copies; seenReplies dedupes them.
The fallback is guarded by turns.length === 0 so new-format sessions (whose
Subgraph scan succeeds) are completely unaffected and never double-counted.
Tests: old-format doc with multiple AgentRound rounds → 1 call whose token
count equals the two non-empty replies joined (the empty tool-call round is
excluded); an uppercase-UUID variant (fails without the case-insensitive
match); and a guard that new-format Subgraph turns are not double-counted.
docs/providers/copilot.md documents the old format and the one-call-per-session
limitation.
12 KiB
Copilot
GitHub Copilot Chat (CLI, VS Code core chat sessions, VS Code extension transcripts, and JetBrains IDE sessions).
- Source:
src/providers/copilot.ts - Loading: eager (
src/providers/index.ts:3) - Test:
tests/providers/copilot.test.ts
Where it reads from
Three JSONL locations plus an optional OpenTelemetry SQLite source (see below). OTel is preferred when present; chatSessions are only discovered when no OTel source is found. Other discovered sources are walked on every run; results merge and dedupe.
- Legacy CLI sessions:
~/.copilot/session-state/ - VS Code core chat sessions:
~/Library/Application Support/Code/User/workspaceStorage/<hash>/chatSessions/*.jsonlplus~/Library/Application Support/Code/User/globalStorage/emptyWindowChatSessions/*.jsonland equivalents on Windows / Linux - VS Code transcripts:
~/Library/Application Support/Code/User/workspaceStorage/<hash>/GitHub.copilot-chat/transcripts/and equivalents on Windows / Linux - 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; legacy JSONL sources only record output tokens. - JetBrains IDE sessions:
~/.config/github-copilot/<ide>/<kind>/<storeId>/copilot-*-nitrite.db(see the JetBrains section). Covers IntelliJ IDEA, PyCharm, RubyMine, etc.
Storage format
JSONL in the first three locations (schemas differ; the parser switches by source type / event shape), a SQLite DB for the OTel source, and a Nitrite (H2 MVStore) .db for the JetBrains source. VS Code core chat sessions use a delta journal: kind:0 sets the root object, kind:1 writes a value at path k, and kind:2 appends items to an array path.
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.
If OTel discovery finds at least one source, workspace chatSessions/*.jsonl and
emptyWindowChatSessions/*.jsonl are skipped. Those journals can mirror the same Copilot
turns under IDs that do not match OTel turn IDs, so CodeBurn prefers the richer OTel data
instead of trying to dedupe across stores.
- Requires Node 22+. The OTel source uses the built-in
node:sqlitemodule (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.
JetBrains IDEs (IntelliJ, PyCharm, …)
The JetBrains Copilot plugin does not write to any of the VS Code or CLI locations above. It persists chat/agent sessions under the shared GitHub Copilot config root, in one store directory per session store:
~/.config/github-copilot/<ide>/<kind>/<storeId>/
copilot-*-nitrite.db # Nitrite (H2 MVStore) — the session content
blobs/
<ide> is a per-IDE dir (iu for IntelliJ IDEA Ultimate, intellij for the
community edition, PyCharm2025.2, …). <kind> ∈ chat-agent-sessions,
chat-sessions, chat-edit-sessions (agent / ask / edit mode). The root follows
XDG rules: $XDG_CONFIG_HOME/github-copilot when set, else
~/.config/github-copilot (macOS / Linux) or %LOCALAPPDATA%\github-copilot
(Windows).
Storage: the Nitrite .db. An H2 MVStore file (header
H:2,block:9,…format:3) of Java-serialized Nitrite documents (NtAgentSession,
NtAgentTurn). It is read as latin1 (byte-offset-stable, lossless) and scanned
— no Java deserializer, no new deps, and it is not SQLite so node:sqlite is
not used. Each assistant reply is a {"__first__":{"type":"Subgraph",…}} blob.
extractResponseText recovers the reply by unescaping one level at a time and,
at the first depth where the record markers appear bare, reading the reply
structurally (the payload is parsed as a delimited JSON-string literal, so a
reply containing its own quotes is never truncated).
Two turn shapes, both handled (a blob is one or the other — verified across every observed store that they never coexist):
- Ask mode — the reply is a
Markdownrecord'stext. - Agent / plan mode (agent sessions,
/plan …, e.g. in PyCharm) — the reply is thereplyfield of anAgentRoundrecord; here theMarkdownrecords hold the user's prompt instead. The mode is decided by the presence of anAgentRoundrecord, and only itsreplyis read — so an agent turn with an empty reply (a failed turn or a pure tool-call round) is billed $0 rather than falling back to the prompt. A multi-round blob contributes every non-empty round's reply.
Sidecar records that plan/agent mode also writes — Thinking (chain-of-thought),
PendingChanges (proposed code diff, stored under content not data),
AskQuestion, Notification, SubTurn, and file-read text results — are
not billable assistant output and are deliberately skipped. User prompts are
the simpler {"<uuid>":{"type":"Value",…}} value-maps.
Old plugin format (≤1.5.x, e.g. 1.5.59-243). Older plugins do not write
per-turn __first__/Subgraph blobs at all — they store the whole session as ONE
binary-framed outer Nitrite document of UUID-keyed Value entries, with the
AgentRound records one escaping level deeper. When the Subgraph scan finds no
turns but the raw file contains AgentRound text, a fallback locates that outer
document (extractJetBrainsDbTurns), runs it through the same
extractResponseText depth-unescape, and emits one session-level call per
document (all rounds' replies joined). Cost and tokens are correct; only the
per-turn call-count granularity is coarser than the new format — an accepted
tradeoff for legacy data. The fallback is gated on the new-format scan yielding
nothing, so current sessions are never affected or double-counted.
(Store dirs may also contain a legacy 00000000000.xd Xodus log from older
plugin versions. On every installation observed it is either empty or shadowed
by the .db, so CodeBurn reads only the .db. If a real .xd-only session ever
surfaces, add a reader with a captured fixture.)
-
No token accounting. No store records token counts. Output tokens are estimated from the reply text via
estimateTokens(CHARS_PER_TOKEN = 4, as for Cursor and legacy Copilot JSONL); input tokens are 0; every JetBrains call is markedcostIsEstimated: true. -
Errored turns. A failed generation ("Sorry, an error occurred …") is stored as an assistant blob with an error status and no reply text; it is detected and billed $0 (not conflated with an empty success). In agent mode a failed turn has an empty
AgentRoundreply — the parser does not fall back to the promptMarkdown, so the user's words are never billed as the assistant's output. -
Per-turn model. The model varies per turn within one
.db. It is recovered from inside the assistant blob when present, else a store-wide default, else a generic Copilot bucket. Dotted Claude names are normalised to canonical ids (claude-opus-4.5→claude-opus-4-5); GPT/Gemini names kept verbatim. -
Duplicates. The store keeps several byte-copies of each reply (original, lowercased, revisions); assistant turns are de-duplicated by reply content.
-
One
.dbholds many chat tabs. A single store.dbcontains multiple conversations, each with an internal GUID and an evolving title (New Agent Session→ auto-name → final title). CodeBurn recovers theGUID → titlemap (extractJetBrainsConversations, keeping the latest non-default title), attributes each turn to the nearest preceding conversation GUID, and emits one session per conversation (not one per.db). Reply content is de-duplicated per conversation. -
Project. Resolved in three tiers, most authoritative first:
projectNamefield (plugin 1.12+). Recent plugins serialize the repo label directly on the session doc (extractJetBrainsProjectName) — the JetBrains analogue of the OTel source'sgithub.copilot.git.repository. Cross-kind join: the billable turns live inchat-agent-sessions, but theprojectNameis usually written only into the siblingchat-sessions/chat-edit-sessionsstore. Discovery (resolveJetBrainsProjectNames) joins them by store id so the agent session inherits the label from whichever store recorded it. Read length-prefixed (JavaTC_STRING) so an embedded quote/newline can't truncate it..gitwalk-up (older plugins / noprojectName). For eachfile://URI a chat referenced, walk UP the real filesystem to the nearest ancestor containing a.gitand use that repo's basename (e.g.pinot).copilot-jetbrainsbucket when neither signal exists (chat referenced no files and noprojectNamewas recorded, or the repo no longer exists on disk).
The conversation title is a chat-thread name, NOT a project — it is the session label (
userMessage) and deliberately kept out ofprojectso it does not pollute the By-Project view. Note thatbg-agent-sessions/(a newer kind dir holdingcopilot-agent-snapshots.db/copilot-session-metadata.db) is not scanned: those DBs carry file snapshots and metadata, not billable turns, and the same session's turns are already read fromchat-agent-sessions. -
Override the root with
CODEBURN_COPILOT_JETBRAINS_DIR.
Caching
None for the JSONL sources. The OTel source uses a durable cache (see above).
Deduplication
Legacy JSONL and transcript sessions dedupe per messageId. Core chat sessions dedupe per copilot-chatsession:<sessionId>:<requestId>, and are not discovered when an OTel source is present. JetBrains .db turns dedupe per copilot:jb:<conversationId>:<turnIndex> (a per-conversation index, plus reply-content dedup within each conversation). These sources otherwise touch disjoint locations from the VS Code / CLI sources.
If a workspace hash contains at least one chatSessions/*.jsonl file, the provider skips that hash's legacy GitHub.copilot-chat/transcripts/ directory. The core chat session journal is the modern token-bearing source for the same conversations, so reading both would inflate call counts.
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
toolRequestscan be missing or non-array on older sessions; the parser guards against that (copilot.ts:126,:260).- When
outputTokensis 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
messageIdcollision handles this.
When fixing a bug here
- Determine which schema reproduces the bug. The two parsers share little code on purpose; do not unify them unless you understand both formats.
- If the model is misidentified, look at the tool-call ID prefix list and consider whether a new prefix should be added.
- New fixtures go under
tests/fixtures/copilot/and are referenced fromtests/providers/copilot.test.ts.