pi-reduce

pi-reduce is a Pi package that rebuilds the current branch into a smaller session.

It keeps only the message types you want, drops the rest, and writes the result into a brand new Pi session that you continue from immediately.

No summaries are generated in v1. The reduction is deterministic: keep, drop, and truncate only.

Install

pi install npm:pi-reduce

Or from git:

pi install git:github.com/toorusr/pi-reduce

Commands

• /reduce [chat|reasoning|tools|no-tools|advanced|last]
• /reduce-advanced

Presets

• chat — keep user messages and final assistant output only
• reasoning — keep user messages, assistant thinking, assistant comments, and final output
• tools — keep user messages plus tool calls and tool results
• no-tools — keep user messages plus assistant comments and final output
• last — rerun the last reduce config
• advanced — open the full reducer UI

What gets reduced

/reduce always starts from the current active branch context. It does not rewrite your source session. Instead it:

1. reads the current branch context
2. filters messages by type
3. optionally filters tools by name
4. optionally truncates tool arguments and tool results
5. creates a new session
6. switches into the new session immediately

The current model and thinking level are copied to the new session.

Advanced options

/reduce-advanced lets you configure:

Message categories

• user messages
• assistant thinking
• assistant comments from tool-using turns
• assistant final messages
• assistant status / aborted / error messages
• tool calls
• tool results
• user bash executions (! / !!)
• custom / extension messages
• existing branch summaries
• existing compaction summaries

Tool filters

• keep all tools
• keep only selected tools
• exclude selected tools

Truncation

• tool call approx-token budget
• tool call char budget
• tool call line budget
• tool result approx-token budget
• tool result char budget
• tool result line budget
• head or tail truncation for tool results

Output

The final notification shows a compact before/after summary with:

• context reduction bar
• approximate context tokens before vs after
• kept vs removed messages
• key block reductions (thinking, tool calls, tool results)
• recorded source usage totals

The new reduced session also stores provenance in a reduce-source custom entry.

Notes

• Copied messages do not preserve historical assistant usage tags, so the new session starts with 0 recorded usage until you continue chatting.
• Approximate token counts use Pi's own conservative chars / 4 heuristic.
• Tool-result details are replaced with compact reduced metadata so the new session stays light.

Local development

npm install
npm run check

For a quick local test without installing the package:

pi -e /absolute/path/to/pi-reduce