What Gets Recorded

Every AI-assisted commit automatically receives a detailed marker. Here are real examples:

Single model, one prompt:

feat: add dark mode toggle

Impacted by AI (Agent mode: new | Model: claude-sonnet-4.6 | Prompts: 1 | Tokens: claude-sonnet-4-6: 48k in/2k out (41k cached))

Multi-model session — Claude for reasoning, Gemini for search:

refactor: split auth service into separate module

Impacted by AI (Agent mode: new | Model: claude-sonnet-4.6, gemini-3.1-pro-preview | Prompts: 2 | Tokens: claude-sonnet-4-6: 296k in/5k out (243k cached) | gemini-3.1-pro-preview: 104k in/678 out (74k cached))

Reasoning model with thinking tokens:

fix: resolve race condition in async queue

Impacted by AI (Agent mode: copilot | Model: gpt-5.4 | Prompts: 1 | Tokens: gpt-5.4-2026-03-05: 143k in/1k out (118k cached) +333 reasoning)

Sub-agents + inline suggestions in the same session:

docs: rewrite contributing guide

Impacted by AI (Inline + Agent mode: new | Model: claude-sonnet-4.6 | Prompts: 3 | Sub-agents mode: Explore | sub-Agent prompts: 2 | Tokens: claude-sonnet-4-6: 180k in/4k out (155k cached))

How It Works

The extension uses three complementary mechanisms, all running locally.

1. Token Usage via OTEL

The extension activates Copilot's built-in local OpenTelemetry span exporter (github.copilot.chat.otel.dbSpanExporter.enabled), which writes real measured token counts to a local SQLite database (agent-traces.db) — no network required, no third-party telemetry.

At the end of each session, the hook handler queries that database and records per-model token breakdowns directly in the commit marker:

Token data is time-scoped to the current session — spans from previous sessions in the same VS Code window are excluded, so each commit reflects only the tokens consumed for that specific piece of work.

2. Copilot Hooks (Agent Sessions & Sub-agents)

VS Code Copilot Hooks fire lifecycle events during every Copilot chat session. A lightweight Node.js handler listens to five events:

On Stop, the handler also parses the VS Code Copilot Chat log to extract model names — separated into user-selected models ([panel/editAgent] entries) and sub-agent models ([tool/runSubagent*] entries). Parsing is scoped by session ID and timestamp.

State accumulates in .git/ai-tracker-state.json until consumed by the commit-msg hook.

3. Inline Suggestion Tracking (Deterministic)

For ghost-text completions, the extension intercepts acceptance keystrokes with zero false positives:

When an inline suggestion is accepted, the flag is written to .git/AI_IMPACT_PENDING. If an agent session also ran before the commit, both are merged: Impacted by AI (Inline + Agent mode: ...).

4. Git Integration

A global commit-msg hook (auto-installed via git config --global core.hooksPath) fires at every commit across all your repositories. It reads AI_IMPACT_PENDING, appends the marker to the commit message, then removes both the flag and the state file.

Marker Field Reference

Features

• Automatic — Install once; every AI-assisted commit is tagged from that moment on. No per-repo setup.
• Token Tracking — Real measured token counts from Copilot's OTEL pipeline, not estimates.
• Per-Model Breakdown — Each model's input, output, cached, and reasoning tokens recorded separately — ready for cost calculation.
• Reasoning Tokens — Thinking tokens from reasoning models (GPT-5.x, o1, o3) are tracked and labeled +NNN reasoning.
• Session-Scoped — Token queries are time-bounded to the current session; previous commits in the same window don't bleed in.
• Multi-Session Accumulation — Multiple agent sessions before a single commit are merged and their token counts summed.
• Inline + Agent — Tracks both ghost-text acceptances and full chat sessions; merges them when both occur before a commit.
• Global Git Hooks — One hook covers all repositories. No per-repo initialization.
• Privacy First — Everything runs locally. No code, prompts, or token data leaves your machine.

Requirements

• VS Code 1.100.0 or later (Copilot Hooks support)
• GitHub Copilot extension installed
• Git initialized in your repository
• Node.js 22+ (for node:sqlite built-in — included with VS Code's bundled Node)

Core Team

Author	Author	Contributor
@YoavLax	@davidexterman	@GitHub-Copilot

Development

npm run compile        # One-time build
npm run watch          # Watch mode (or press F5 in VS Code)
npm run test           # Run extension tests

Press F5 to launch the Extension Development Host for debugging.

Key Files

License

MIT