@alexleekt/pi-heading

Know where you are at a glance.

A one-line session heading for the Pi coding agent. It summarizes the current goal while Pi works, then replaces it with a short achievement when the run finishes.

What it looks like

Clean up the old chezmoi checkout

After completion:

Removed stale dotfiles and migrated the setup to yadm

The extension uses Pi's native working-message row. There are no borders, custom panels, duplicate transcript cards, or competing animation timers.

Features

| Feature | What it does | |---------|--------------| | Auto-summarized heading | Generates a concise goal after every user message | | Achievement summary | Shows what the agent completed after the final turn | | Stable topic | Keeps a 2–4 word topic label from jittering between related turns | | Branch-aware state | Restores the correct heading after session resume and /tree navigation | | Native lifecycle integration | Finalizes on Pi's agent_settled event, after retries, compaction, and queued follow-ups | | Cancellation-aware calls | Passes Pi's active AbortSignal to heading model requests | | Custom prompts and model | Supports editable prompts and a separate low-cost summarization model | | Extension API | Exposes current state through the heading tool and heading:state event |

Requirements

• Pi coding agent 0.80.4 or newer

Installation

pi install @alexleekt/pi-heading

For local development:

ln -s ~/git/pi-extensions/packages/pi-heading ~/.pi/agent/extensions/pi-heading

Run /reload after changing extension code. Pi loads TypeScript through jiti, so clearing jiti's cache may be necessary when retargeting symlinks.

Usage

The heading updates automatically. No command is required.

/heading

Set the current goal manually:

/heading
Session heading: Migrating from Docker to Kubernetes

/heading-model

Choose a model for topic, goal, and achievement summaries. Reset the override to use the active session model.

/heading-debug

/heading-debug on
/heading-debug off
/heading-debug clear
/heading-debug

Debug mode writes structured prompts, user input, responses, and errors to a private log under Pi's agent directory. The file is restricted to the current user, but it can contain sensitive conversation content; enable it only while diagnosing a problem and clear it afterward.

Agent tool

The extension registers a heading tool:

• action: "get" returns topic, goal, and latest achievement.
• action: "skill" returns the heading behavior guide.

The tool's prompt metadata asks the agent to check the current session goal before changing direction.

Event bus integration

Other extensions can subscribe without importing pi-heading:

pi.events.on("heading:state", (payload) => {
    const { topic, goal, achievement, mode } = payload as {
        topic: string;
        goal: string;
        achievement?: string;
        mode: "goal" | "working" | "achievement" | "idle";
    };
});

See PI-INTEGRATION.md for the payload contract.

Custom prompts

Packaged defaults live in prompts/. To override them, create matching files under:

~/.pi/agent/extensions/pi-heading/prompts/
├── topic.md
├── goal.md
└── achievement.md

If PI_CODING_AGENT_DIR is set, pi-heading follows Pi's configured agent directory instead of hardcoding ~/.pi/agent.

Each prompt supports YAML frontmatter with max_words:

---
max_words: 4
---
Summarize the user's message as a concise topic label.

Message: {message}

Placeholders:

• {message} — input being summarized
• {goal} — current goal, available to the achievement prompt
• {max_words} — parsed frontmatter limit

Lifecycle

sequenceDiagram
    participant User
    participant Pi
    participant Heading as pi-heading
    participant Model as Summary model

    Pi->>Heading: session_start / session_tree
    Heading->>Heading: replay latest branch heading

    User->>Pi: submit prompt
    Pi->>Heading: before_agent_start
    Heading->>Pi: setWorkingMessage(prompt placeholder)
    Heading-->>Model: topic + goal (non-blocking, abort-aware)
    Pi->>Heading: agent_start / turn_start
    Heading->>Pi: setWorkingMessage(goal)

    alt Intermediate tool turn
        Pi->>Heading: turn_end with toolResults
        Heading->>Heading: keep goal; skip achievement call
    else Final text turn
        Pi->>Heading: turn_end without toolResults
        Heading-->>Model: achievement (non-blocking, abort-aware)
        Heading->>Pi: setWorkingMessage(achievement)
    end

    Pi->>Heading: agent_settled
    Heading->>Pi: keep latest goal or achievement

agent_settled is intentionally used instead of agent_end: Pi can retry, compact and retry, or process queued follow-ups after a low-level agent run ends.

Prompt evaluation

bun tools/prompt-eval.ts topic
bun tools/prompt-eval.ts goal
bun tools/prompt-eval.ts topic-goal firepass test-cases-comprehensive.json

The optimizer mutates prompt files in place, so back them up first:

bun tools/prompt-eval.ts optimize topic prompts/topic.md \
  "Concise 1-4 word noun phrases, no articles" \
  90 firepass test-cases-comprehensive.json

Development

npm run typecheck
npm test
npm run pack-smoke

pack-smoke packs the npm artifact, verifies all transitive runtime files are present, installs it into a temporary project with declared peers, and imports the TypeScript entrypoint through Pi's jiti loader.

License

MIT