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.