pi-live-throughput

A single-line live tokens/sec display for the Pi coding agent.

While an assistant response streams, the extension shows its rolling throughput, average throughput, estimated output tokens, elapsed time, and model:

⚡ 92.3 tok/s · avg 84.5 tok/s · 1.2k tok · 14.2s · deepseek-v4-flash

When streaming finishes, it replaces the live metrics with a final summary that stays visible until the next assistant response starts. Prompt fields are added when Pi exposes usable normalized values:

✓ 512 tok in 2.0s · 256 tok/s avg · peak 319 tok/s · input 1.2k tok · cache read 8.0k tok · TTFT 420ms · approx. prompt 2900 tok/s · deepseek-v4-flash

Live figures use Pi's cumulative provider-reported usage.output value when it advances during streaming. Providers that expose usage only after completion fall back to text, thinking, and tool-call delta estimates, identified by est. rates and ~ token counts. The final token count always uses the provider-reported value.

Prompt and cache metrics

Pi normalizes prompt usage into separate input, cacheRead, and cacheWrite counts. input is the uncached, non-cache-write portion; cache-read tokens are shown separately and are never described as tokens processed by the model. Because Pi initializes unavailable usage fields to zero, this extension reports only positive prompt/cache counts rather than presenting a zero as confirmed provider data.

TTFT (time to first output) is measured from Pi's before_provider_request boundary to the first substantive text, thinking, or tool-call output event. It is omitted if either boundary is unavailable. TTFT is an end-to-end observation: it can include network latency, provider queueing and routing, cache lookup, and model startup, not just model prefill.

approx. prompt is a best-effort estimate calculated as (input + cacheWrite) / TTFT. It is shown only when both a positive processed prompt-token count and a positive TTFT are available. Cache-read tokens are excluded. The estimate is not true model prefill throughput because its timing contains the end-to-end latency above.

Install

Install from npm:

pi install npm:pi-live-throughput

Alternatively, install directly from GitHub:

pi install git:github.com/apetersson/pi-live-throughput

For local development, install the checkout instead:

pi install /absolute/path/to/pi-live-throughput

Use /reload if Pi was already running when you installed or changed the extension.

Commands

The widget is enabled above the editor by default.

| Command | Effect | | -------------------- | ------------------------------------------------------ | | /throughput | Toggle the display on or off | | /throughput on | Enable the previously selected display mode | | /throughput off | Hide the display | | /throughput widget | Enable the full single-line widget above the editor | | /throughput status | Enable a compact footer status instead | | /throughput reset | Reset an active measurement or clear the final summary |

Development

This project uses pnpm only. The verification command checks Prettier formatting, strict TypeScript compilation, zero-warning ESLint, and the test suite:

pnpm install --frozen-lockfile
pnpm run verify

Apply formatting with pnpm run format. Run individual checks with pnpm run format:check, pnpm run check, pnpm run lint, or pnpm run test.

To load the local extension without installing it:

pi -e ./src/index.ts

License

MIT