pi-response-stats

A lightweight Pi extension that tracks and displays LLM response performance in the footer: tokens per second and response time, per agent run and cumulative across the session.

The footer shows the current run's TPS and duration alongside session averages:

⚡123/99 ⏱32s/1m 54s

What it shows

• Current run: TPS and duration of the most recent agent run, live while running (every thinking block and tool call counts)
• Session totals: average TPS and total time across all runs in the current session; the total time ticks live during a run

Statistics are stored per session and branch:

| Mode | Behavior | |---|---| | New session | Resets to zero | | /resume | Restores that session's active-branch statistics | | /reload | Restores the current statistics | | /fork | Inherits statistics from the selected branch | | /tree | Restores statistics for the branch you navigate to |

If a session or branch has no stored snapshot, it starts at ⚡0/0 ⏱0s/0s.

Format

The stats line is configurable. Set format in ~/.pi/agent/response-stats.json. A leading \n renders the stats on their own line below pi's stats (the default); without the prefix they append inline to pi's stats line, after a single hardcoded space:

{ "format": "\n⚡{runTps}/{avgTps} ⏱{runDuration}/{totalDuration}" }

Placeholders

| Placeholder | Kind | No-data / zero behavior | Example (run: 1h 2m 3s · total: 0h 1m 54s · TPS 123 · 421 tok) | |---|---|---|---| | {runTps} | int | 0 | 123 | | {avgTps} | int | 0 | 99 | | {runTokens} | int | 0 | 421 | | {totalTokens} | int | 0 | 3842 | | {runDuration} | string, pre-formatted | 0s | 1h 2m | | {totalDuration} | string, pre-formatted | 0s | 1m 54s | | {runHours} {runMinutes} {runSeconds} | int | always renders, incl. 0 | 1, 2, 3 | | {totalHours} {totalMinutes} {totalSeconds} | int | always renders, incl. 0 | 0, 1, 54 | | {runHoursIfAny} | string, conditional | (empty) | 1h | | `{runMinutesIfAny}` | string, conditional | (empty) | 2m | | {runSecondsIfAny} | string, conditional | (empty) | 3s | | `{totalHoursIfAny}` | string, conditional | (empty) | (empty) | | `{totalMinutesIfAny}` | string, conditional | (empty) | 1m | | {totalSecondsIfAny} | string, conditional | `` (empty) | 54s |

Logic

1. Substitute every {name} (and optional {name:spec} for numbers) with its value.
2. IfAny placeholders expand to value + unit when non-zero, empty string when zero.
3. Collapse consecutive spaces to one, trim ends (this removes the gaps left by vanished IfAny segments).
4. Unknown placeholders stay literal so typos are visible.

Number specs follow .NET style: 0 (integer), 0.0 (one decimal), 0.## (up to two, no trailing zeros).

Examples (run: 32s · total: 1m 54s · TPS 123/99)

| Format string | Result | |---|---| | ⚡{runTps}/{avgTps} ⏱{runDuration}/{totalDuration} (default) | ⚡123/99 ⏱32s/1m 54s | | ⚡{runTps}/{avgTps} (no \n prefix) | appended inline to pi's stats line, after one space | | same, before first run | ⚡0/0 ⏱0s/0s | | ⏱{runHoursIfAny} {runMinutesIfAny} {runSecondsIfAny} | ⏱ 32s | | ⏱{runHours}h {runMinutes}m {runSeconds}s | ⏱0h 0m 32s | | {runHoursIfAny} {runMinutesIfAny} {runSecondsIfAny} / {totalHoursIfAny} {totalMinutesIfAny} {totalSecondsIfAny} | 32s / 1m 54s | | {runTps:0.0}/{avgTps} | 123.0/99 | | {runTokens} tok | 421 tok |

Install

# From npm (published releases)
pi install npm:pi-response-stats

# From git (unpinned; updates with `pi update --extensions`)
pi install git:github.com/that-lucas/pi-response-stats

Or copy response-stats.ts to ~/.pi/agent/extensions/ and run /reload.

Behavior

Works automatically, no commands or shortcuts. The line is always visible; values fill in as runs complete.