Copilot CLI Cost Meter

A small GitHub Copilot CLI extension that adds /cost, a read-only estimate of current session token billing using GitHub Copilot AI Credits model pricing.

Important

This is a personal, best-effort estimate from local Copilot CLI session metrics. Do not treat it as authoritative billing data; always use the official GitHub billing pages for your account or organization as the source of truth.

The pricing table is hardcoded from the public GitHub Copilot AI Credits documentation as checked on May 5, 2026. It does not dynamically fetch or adjust to future pricing changes, so treat this as a proof of concept for personal education unless you update the code when prices change.

It intentionally keeps the output minimal: model, token bucket, and estimated AI Credit spend.

Pricing source: https://docs.github.com/en/copilot/reference/copilot-billing/models-and-pricing

Architecture

flowchart TD
    User["User runs /cost"] --> CLI["GitHub Copilot CLI"]
    CLI --> Extension["cost-meter extension"]
    Extension --> Metrics["session.rpc.usage.getMetrics()"]
    Metrics --> Buckets["Billing buckets<br/>input, cached input, cache write, output"]
    Buckets --> Pricing["Model pricing table<br/>GitHub AI Credits rates"]
    Pricing --> Table["Markdown table<br/>model | tokens | cost"]
    Table --> User

Loading

How robust is it?

This is deliberately simple: one extension file, no runtime dependencies, no network calls, no secrets, and no filesystem writes during use. It reads the Copilot CLI session's own usage metrics through the extension SDK and formats a billing estimate.

The main maintenance point is the hardcoded pricing table. If GitHub changes model names or rates, update extension/extension.mjs from the official pricing page and reinstall.

Install

Clone the repo, then run the installer for your shell.

git clone https://github.com/adstuart/copilot-cli-cost-meter.git
cd copilot-cli-cost-meter

Windows PowerShell

.\install.ps1

macOS / Linux

./install.sh

Restart Copilot CLI after installation. If your Copilot CLI supports extension reloads in-session, you can reload instead of restarting.

Use

In Copilot CLI:

/cost

The command prints only a table:

| Model | Tokens | Cost |
| --- | ---: | ---: |
| gpt-5.5 input | 19,729 | 10 credits / $0.10 |
| gpt-5.5 cached input | 243,200 | 12 credits / $0.12 |
| gpt-5.5 output | 765 | 2 credits / $0.02 |
| **Total** | **263,694** | **24 credits / $0.24** |

Billing notes

• 1 AI Credit is treated as $0.01 USD.
• Cached input is not double-counted: full-rate input is calculated as inputTokens - cacheReadTokens - cacheWriteTokens.
• Reasoning tokens are not shown as a separate billing row; they are treated as part of output for this simplified view.
• This is an estimate. Exact GitHub billing may differ from local session metrics.

Development

Check syntax:

npm run check