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:@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:@plannotator/pi-extension

Pi version and project trust

Plannotator requires Pi 0.79.1 or newer. Updating only the Plannotator extension does not repair the security behavior of an older Pi host; update Pi itself before loading the extension.

Pi 0.79 introduced project trust for repository-local inputs. In interactive sessions, Pi asks before loading project settings, instructions, resources, and packages, and can save the decision for that working directory. Plannotator honors the same decision for .pi/plannotator.json.

Noninteractive sessions ignore project-local inputs unless the project already has a saved trust decision or Pi is started with --approve (-a). Use --no-approve (-na) to disable project inputs for a run even when the project was previously trusted.

Uninstall

Remove a standalone Pi installation with:

pi remove npm:@plannotator/pi-extension

If Pi was configured by the full Plannotator installer, plannotator uninstall also detects and removes the extension through Pi.

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-plan-mode or Ctrl+Alt+P. The command accepts an optional file path argument (/plannotator-plan-mode plans/auth.md) or prompts you to choose one interactively.

In plan mode the agent is restricted — destructive commands are blocked, writes are limited to the plan file. It explores your codebase, 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-plan-mode slash command:

import { PLANNOTATOR_REQUEST_CHANNEL } from "@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

{
  "executionMode": "automatic",
  "defaults": {
    "model": { "provider": "anthropic", "id": "claude-sonnet-4-5" },
    "thinking": "medium",
    "activeTools": ["read", "bash"],
    "statusLabel": "Ready",
    "instructions": "Optional phase-entry message template"
  },
  "phases": {
    "planning": {
      "model": null,
      "thinking": null,
      "activeTools": ["grep", "find", "ls", "plannotator_submit_plan"],
      "statusLabel": "⏸ plan",
      "instructions": "[PLANNING]\nPlan file: ${planFilePath}"
    },
    "executing": {
      "model": { "provider": "anthropic", "id": "claude-sonnet-4-5" },
      "thinking": "high",
      "activeTools": [],
      "statusLabel": "",
      "instructions": "[EXECUTING]\nExecute ${planFilePath}.\n\nEntry checklist:\n${todoList}"
    },
    "reviewing": {
      "instructions": "..."
    }
  }
}

Option reference

Option	Type	Meaning
executionMode	automatic | external	automatic executes approved plans in the current Pi session; external emits a handoff event and returns to idle
defaults	object	Base values applied to every phase before phase-specific overrides
phases	object	Phase-specific overrides
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	off | minimal | low | medium | high | xhigh | max | null	Sets the thinking level; null leaves the current level unchanged. Pi clamps a level the running model does not support, and an unrecognized value is reported as a warning instead of being ignored
activeTools	string[] | null	Tools to turn on for the phase. Setting it replaces the inherited list rather than adding to it (phase overrides defaults, your config overrides the built-in one); [] or null means no extra phase tools. plannotator_submit_plan is always enabled during planning regardless of this setting
statusLabel	string | null	Optional UI label for the phase; empty/null clears it
instructions	string | null	Phase framing template, delivered once as a hidden conversation message when the phase is entered; empty/null disables the framing message. Replaces the removed systemPrompt key, which is now ignored with a warning

Prompt variables

Use these inside instructions strings. They render once, when the phase is entered:

• ${planFilePath} — current plan file path
• ${todoList} — remaining checklist items as markdown checkboxes (an entry-time snapshot; live updates arrive as separate per-turn messages)
• ${completedCount} — completed checklist count
• ${totalCount} — total checklist count
• ${remainingCount} — remaining checklist count
• ${phase} — current runtime phase (planning, executing, reviewing, or idle)

Behavior notes

• Plannotator never modifies Pi's system prompt. Pi's base prompt (AGENTS.md context, the skills catalog, tools guidance, --append-system-prompt text, working directory) always reaches the model untouched. Phase framing is injected as conversation messages instead, so prompt-cache invalidation reduces to appends at the tail of the conversation plus one history adjustment per phase transition.
• The instructions template is delivered exactly once per phase entry as a hidden message; later prompts in the same phase inject nothing. During execution, a small todo-status message is added per prompt as steps complete. Only the newest framing for the current phase is kept in model context: stale framing from other phases or earlier plan cycles is filtered out, and everything Plannotator injected is filtered while idle.
• The one exception while idle is a hidden "plan mode off" notice, delivered on the first prompt after plan mode is turned off (or a plan completes/hands off), which tells the model the planning/execution instructions no longer apply. It is delivered once but then stays anchored in model context for the rest of the idle session; unlike phase framing it is not re-delivered after a compaction. Sessions that never enter plan mode inject nothing at all.
• Executing instructions that do not reference ${todoList} get the entry-time todo snapshot appended automatically, so the first executing prompt always carries the checklist.
• The old systemPrompt config key is obsolete and ignored; a warning at session start points to instructions.
• Unknown template variables trigger a warning in the UI and are rendered as empty strings.
• activeTools replaces the list it inherits — it does not merge with it. Defining phases.planning.activeTools in your own config supersedes the built-in ["grep", "find", "ls", "plannotator_submit_plan"] entirely, so list every tool you want for that phase.
• The resolved list is then turned on alongside whatever tools are already active in the session, so Plannotator still preserves tools provided by other extensions, and on phase exit it turns off only the tools it added.
• plannotator_submit_plan is always enabled during planning even if your activeTools omits it — the planning instructions tell the model to call it, so the phase cannot complete without it.
• Execution progress remains dynamic ([DONE:n] + checklist tracking), even if statusLabel is set.
• executionMode defaults to automatic, preserving the existing approval-to-execution flow.
• In external mode, approval restores the pre-planning model, thinking level, and active tools before emitting the handoff event.

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 VCS changes in the code review UI. Annotate specific lines, switch between the modes supported by the detected Git, GitButler, or JJ provider, and submit feedback that gets sent to the agent. Pass --git or --gitbutler to force that provider; GitButler requires but 0.21.0 or newer on PATH.

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.

External plan execution handoff

Set executionMode to external when another Pi extension should orchestrate an approved plan instead of letting Plannotator execute it in the current session:

{
  "executionMode": "external"
}

After approval, Plannotator returns to idle and emits plannotator:plan-approved with:

{
  cwd: string;
  planFilePath: string;
  planContent: string;
  feedback?: string;
}

planFilePath is the path exactly as it was submitted, so it is normally relative to cwd. Resolve it against cwd before reading the file rather than against the companion extension's own working directory.

Companion extensions can subscribe through the shared event bus:

import { PLANNOTATOR_PLAN_APPROVED_CHANNEL } from "@plannotator/pi-extension/plannotator-events";
import { resolve } from "node:path";

pi.events.on(PLANNOTATOR_PLAN_APPROVED_CHANNEL, (event) => {
  const planPath = resolve(event.cwd, event.planFilePath);
  // Compile and dispatch the approved plan with an external orchestrator.
});

As with plannotator:request, the channel is a plain string, so a companion can listen with pi.events.on("plannotator:plan-approved", ...) and never import Plannotator internals. The constant and the PlannotatorPlanApprovedEvent type are exported purely as a typing convenience.

Plannotator does not send Continue with the approved plan, enter its executing phase, or track checklist progress in this mode. The companion extension owns execution after the handoff.

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.

URL targets work too. A loopback http URL that answers with an HTML page (a running dev app, e.g. http://localhost:5173) opens live: the app is served through a local reverse proxy and annotated in place, with HMR and WebSockets passed through. --static forces the classic markdown conversion; --app requires a live session and errors instead of falling back. Live sessions are unavailable in remote mode (PLANNOTATOR_REMOTE).

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-plan-mode	Toggle plan mode. The agent writes a markdown plan file anywhere in the working directory and submits its path
/plannotator-review	Open code review UI for current changes
/plannotator-annotate <file>	Open markdown file in annotation UI
/plannotator-last	Annotate the last assistant message

Flags

Flag	Description
--plan	Start in plan mode

Keyboard shortcuts

Shortcut	Description
Ctrl+Alt+P	Toggle plan mode

How it works

By default, the extension manages a state machine: idle → planning → executing → idle. With external execution enabled, approval follows idle → planning → idle and emits the handoff event.

During planning:

• All tools from other extensions remain available
• Bash is unrestricted — the agent is guided by the planning instructions not to run destructive commands
• Writes and edits restricted to the plan file only

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