Plannotator for Pi

Plannotator integration for the Pi coding agent. Adds file-based plan mode with a visual browser UI for reviewing, annotating, and approving agent plans.

Install

From npm (recommended):

pi install npm:@blazed/plannotator-pi-extension

From source:

git clone https://github.com/backnotprop/plannotator.git
pi install ./plannotator/apps/pi-extension

Try without installing:

pi -e npm:@blazed/plannotator-pi-extension

Build from source

If installing from a local clone, build the HTML assets first:

cd plannotator
bun install
bun run build:pi

This builds the plan review and code review UIs and copies them into apps/pi-extension/.

Usage

Plan mode

Start Pi in plan mode:

pi --plan

Or toggle it during a session with /plannotator or Ctrl+Alt+P. The agent chooses a markdown plan path, or you can pass one explicitly (/plannotator plans/auth.md). By default, the planning prompt recommends a session-unique file under ~/.pi/agent/plannotator-plans/<project>/<session-or-task-slug>.md.

In plan mode the agent is restricted — destructive commands are blocked, writes are limited to markdown plan files under the working directory or configured external planRoot (default ~/.pi/agent/plannotator-plans). It explores your codebase with structured tools, asks clarifying questions when needed, then writes a plan using markdown checklists:

- [ ] Add validation to the login form
- [ ] Write tests for the new validation logic
- [ ] Update error messages in the UI

When the agent calls plannotator_submit_plan, the Plannotator UI opens in your browser. You can:

• Approve the plan to begin execution
• Deny with annotations to send structured feedback back to the agent
• Approve with notes to proceed but include implementation guidance

The agent iterates on the plan until you approve, then executes with full tool access. On resubmission, Plan Diff highlights what changed since the previous version.

Programmatic plan-mode control

Other Pi extensions can enter, exit, toggle, or query Plannotator plan mode through the shared Pi event bus without invoking the /plannotator slash command:

import { PLANNOTATOR_REQUEST_CHANNEL } from "@blazed/plannotator-pi-extension/plannotator-events";

const response = await new Promise((resolve) => {
  pi.events.emit(PLANNOTATOR_REQUEST_CHANNEL, {
    requestId: crypto.randomUUID(),
    action: "plan-mode",
    payload: { mode: "enter" }, // "enter" | "exit" | "toggle" | "status"
    respond: resolve,
  });
});

A handled response returns the resulting phase, for example { status: "handled", result: { phase: "planning" } }.

Configuring per-phase behavior

Plannotator loads configuration in three layers:

1. Built-in base config shipped with the package: plannotator.json
2. Global user config: ~/.pi/agent/plannotator.json
3. Project-local config: <cwd>/.pi/plannotator.json

Later layers overwrite earlier ones. If a field is omitted, it inherits the value from lower-precedence layers. If a value is set to null, an empty string, or an empty array, it clears the inherited value instead of merging it. You can also set defaults or an entire phase object to null to clear all inherited settings from lower-precedence layers.

Top-level shape

{
  "planRoot": "~/.pi/agent/plannotator-plans",
  "jjDefaultDiffType": "jj-line",
  "defaults": {
    "model": { "provider": "anthropic", "id": "claude-sonnet-4-5" },
    "thinking": "medium",
    "activeTools": ["read", "bash"],
    "statusLabel": "Ready",
    "systemPrompt": "Optional prompt template"
  },
  "phases": {
    "planning": {
      "model": null,
      "thinking": null,
      "activeTools": ["grep", "find", "ls", "ask_user_question", "jj_context", "plannotator_submit_plan"],
      "statusLabel": "⏸ plan",
      "systemPrompt": "[PLANNING]\n${planFileGuidance}"
    },
    "executing": {
      "model": { "provider": "anthropic", "id": "claude-sonnet-4-5" },
      "thinking": "high",
      "activeTools": [],
      "statusLabel": "",
      "systemPrompt": "[EXECUTING]\nRemaining steps:\n${todoList}"
    }
  }
}

Option reference

Option	Type	Meaning
defaults	object	Base values applied to every phase before phase-specific overrides
phases	object	Phase-specific overrides
planRoot	string | null	External base directory for plan files; defaults to ~/.pi/agent/plannotator-plans. Planning prompts recommend a sanitized project subdirectory and unique filename under it
jjDefaultDiffType	jj-current | jj-last | jj-line | jj-evolog | jj-all | null	Default JJ diff view for code review; the built-in Pi config uses jj-line
phases.planning	object	Settings for planning mode
phases.executing	object	Settings for execution mode
phases.reviewing	object	Reserved for future review-mode customization
model	{ provider, id } | null	Sets the model for the phase; null leaves the current model unchanged
thinking	minimal | low | medium | high | xhigh | null	Sets the thinking level; null leaves the current level unchanged
activeTools	string[] | null	Extra tools to enable for the phase; [] or null means no extra phase tools
statusLabel	string | null	Optional UI label for the phase; empty/null clears it
systemPrompt	string | null	Phase system prompt template; empty/null disables prompt injection

Prompt variables

Use these inside systemPrompt strings:

• ${planFilePath} — current plan file path
• ${planRoot} — resolved external plan root (default ~/.pi/agent/plannotator-plans, unless cleared)
• ${planFileGuidance} — ready-to-use guidance for choosing the correct plan path
• ${todoList} — remaining checklist items as markdown checkboxes
• ${completedCount} — completed checklist count
• ${totalCount} — total checklist count
• ${remainingCount} — remaining checklist count
• ${phase} — current runtime phase (planning, executing, reviewing, or idle)

Behavior notes

• Unknown template variables trigger a warning in the UI and are rendered as empty strings.
• activeTools are additive with the tools currently active in the session, so Plannotator still preserves tools provided by other extensions.
• Execution progress remains dynamic ([DONE:n] + checklist tracking), even if statusLabel is set.
• planRoot defaults to ~/.pi/agent/plannotator-plans; plan write/edit/submit guards allow markdown files under that external tree in addition to the working directory. Set planRoot to null or an empty string in a higher-precedence config to clear it. Non-markdown files and path traversal are rejected.
• Planning prompts prefer structured tools such as read, grep, find, ls, ask_user_question, search/content tools, and jj_context. jj_todo is only for planning previews: create/update must set dryRun: true and fresh: false.

Example files

• Built-in base config shipped with the package: apps/pi-extension/plannotator.json
• Global user override: ~/.pi/agent/plannotator.json
• Project-local override: <cwd>/.pi/plannotator.json

Code review

Run /plannotator-review to open your current changes in the code review UI. Annotate specific lines, switch between diff views, and submit feedback that gets sent to the agent. In JJ workspaces the built-in Pi config defaults to the jj-line diff view. For PR reviews inside a JJ repo, Git local checkout/worktree behavior is intentionally disabled unless you pass --git; --local alone is not enough.

Shared Plannotator event API

Plannotator also listens on the shared plannotator:request event channel so other extensions can reuse the same browser review flows without importing Plannotator internals.

Supported actions and payloads:

• plan-review: { planContent, planFilePath? }
• review-status: { reviewId }
• code-review: { cwd?, defaultBranch?, diffType? }
• annotate: { filePath, markdown?, mode?, folderPath? }
• annotate-last: { markdown? }
• archive: { customPlanPath? }

Plan review is asynchronous:

• callers send plannotator:request with action plan-review
• Plannotator opens the browser review and immediately responds with { status: "handled", result: { status: "pending", reviewId } }
• when the human approves or rejects in the browser, Plannotator emits plannotator:review-result with { reviewId, approved, feedback, savedPath?, agentSwitch?, permissionMode? }
• callers can query review-status with the same reviewId to recover from startup races or session restarts

The other shared actions remain request/response flows. Payloads are intentionally minimal and only include fields the shared implementation actually uses.

Markdown annotation

Run /plannotator-annotate <file.md> to open any markdown file in the annotation UI. Useful for reviewing documentation or design specs with the agent.

Annotate last message

Run /plannotator-last to annotate the agent's most recent response. The message opens in the annotation UI where you can highlight text, add comments, and send structured feedback back to the agent.

Archive browser

The Plannotator archive browser is available through the shared event API as archive, which opens the saved plan/decision browser for future callers. The orchestrator does not expose a dedicated archive command yet.

Progress tracking

During execution, the agent marks completed steps with [DONE:n] markers. Progress is shown in the status line and as a checklist widget in the terminal.

Commands

Command	Description
/plannotator	Toggle plan mode. The agent writes a markdown plan file under the working directory or configured external planRoot, then submits its path
/plannotator-review	Open code review UI for current changes or PRs; in JJ repos use --git to intentionally opt into Git local checkout behavior
/plannotator-annotate <file>	Open markdown file in annotation UI
/plannotator-last	Annotate the last assistant message

Flags

Flag	Description
--plan	Start in plan mode
--git	For review commands, force Git behavior. Required before PR reviews in JJ repos use Git local checkout/worktree behavior
--local	For PR review commands, request local checkout in Git mode; in JJ repos this has no effect unless --git is also supplied
--no-local	For PR review commands, force remote/no-local PR diff behavior

Keyboard shortcuts

Shortcut	Description
Ctrl+Alt+P	Toggle plan mode

How it works

The extension manages a state machine: idle → planning → executing → idle.

During planning:

• All tools from other extensions remain available
• Structured tools are preferred; bash should be used sparingly for tests/build metadata or CLIs when no structured tool fits
• Writes and edits are restricted to markdown plan files under the working directory or configured planRoot During executing:
• Full tool access: read, bash, edit, write
• Progress tracked via [DONE:n] markers in agent responses
• Plan re-read from disk each turn to stay current

State persists across session restarts via Pi's appendEntry API.

Requirements

• Pi >= 0.74.0