@tintinweb/pi-tasks

A pi extension that brings Claude Code-style task tracking and coordination to pi. Track multi-step work with structured tasks, dependency management, and a persistent visual widget.

Status: Early release.

https://github.com/user-attachments/assets/86b09bd1-6882-4b0c-be20-ea866dd44b6a

Features

• 7 LLM-callable tools — TaskCreate, TaskList, TaskGet, TaskUpdate, TaskOutput, TaskStop, TaskExecute — matching Claude Code's exact tool specs and descriptions
• Persistent widget — live task list above the editor with ✔/◼/◻ status icons, strikethrough for completed tasks, star spinner (✳✽) for active tasks with elapsed time and token counts
• System-reminder injection — periodic <system-reminder> nudges appended to tool results when task tools haven't been used recently (matches Claude Code's behavior)
• Task state persistence — current task state injected into system prompt on every agent loop, surviving context compaction
• Prompt guidelines — system prompt guidelines nudge the LLM to use task tools for complex work
• Dependency management — bidirectional blocks/blockedBy relationships with warnings for cycles, self-deps, and dangling references
• Shared task lists — multiple pi sessions can share a file-backed task list for agent team coordination
• File locking — concurrent access is safe when multiple sessions share a task list
• Background process tracking — track spawned processes with output buffering, blocking wait, and graceful stop
• Subagent integration — tasks with agentType can be executed as subagents via TaskExecute (requires @tintinweb/pi-subagents). Auto-cascade mode flows through the task DAG automatically when enabled.

Install

pi install npm:@tintinweb/pi-tasks

Or load directly for development:

pi -e ./src/index.ts

Widget

The extension renders a persistent widget above the editor:

● 4 tasks (1 done, 1 in progress, 2 open)
  ✔ Design the flux capacitor
  ✳ Acquiring plutonium… (2m 49s · ↑ 4.1k ↓ 1.2k)
  ◻ Install flux capacitor in DeLorean › blocked by #1
  ◻ Test time travel at 88 mph › blocked by #2, #3

Icon	Meaning
✔	Completed (strikethrough + dim)
◼	In-progress (not actively executing)
◻	Pending
✳/✽	Animated star spinner — actively executing task (shows activeForm text, elapsed time, token counts)

Tools

TaskCreate

Create a structured task. Used proactively for complex multi-step work.

Parameter	Type	Required	Description
subject	string	yes	Brief imperative title
description	string	yes	Detailed context and acceptance criteria
activeForm	string	no	Present continuous form for spinner (e.g., "Running tests")
agentType	string	no	Agent type for subagent execution (e.g., "general-purpose", "Explore")
metadata	object	no	Arbitrary key-value pairs

→ Task #1 created successfully: Fix authentication bug

TaskList

List all tasks with status, owner, and blocked-by info.

#1 [pending] Fix authentication bug
#2 [in_progress] Write unit tests (agent-1)
#3 [pending] Update docs [blocked by #1, #2]

Sort order: pending first, then in-progress, then completed (each group by ID).

TaskGet

Get full details for a specific task.

Task #2: Write unit tests
Status: in_progress
Owner: agent-1
Description: Add tests for the auth module
Blocked by: #1
Blocks: #3

Shows owner (if set) and ALL dependency edges (including completed blockers) — raw data.

TaskUpdate

Update task fields, status, metadata, and dependencies.

Parameter	Type	Description
taskId	string	Task ID (required)
status	pending / in_progress / completed / deleted	New status
subject	string	New title
description	string	New description
activeForm	string	Spinner text
owner	string	Agent name
metadata	object	Shallow merge (null values delete keys)
addBlocks	string[]	Task IDs this task blocks
addBlockedBy	string[]	Task IDs that block this task

→ Updated task #1 status
→ Updated task #2 owner, status
→ Updated task #3 blocks
→ Updated task #3 blocks (warning: cycle: #3 and #1 block each other)
→ Updated task #1 deleted

Setting status: "deleted" permanently removes the task.

Dependencies are bidirectional: addBlocks: ["3"] on task 1 also adds blockedBy: ["1"] to task 3.

TaskOutput

Retrieve output from a background task process.

Parameter	Type	Default	Description
task_id	string	—	Task ID (required)
block	boolean	true	Wait for completion
timeout	number	30000	Max wait time in ms (max 600000)

TaskStop

Stop a running background task process. Sends SIGTERM, waits 5 seconds, then SIGKILL.

Parameter	Type	Description
task_id	string	Task ID to stop

TaskExecute

Execute one or more tasks as background subagents. Requires @tintinweb/pi-subagents.

Parameter	Type	Description
task_ids	string[]	Task IDs to execute (required)
additional_context	string	Extra context appended to each agent's prompt
model	string	Model override (e.g., "sonnet", "haiku")
max_turns	number	Max turns per agent

Tasks must be pending, have agentType set, and all blockedBy dependencies completed. Each task spawns as an independent background subagent.

With auto-cascade enabled (via /tasks → Settings), completed tasks automatically trigger execution of their unblocked dependents — flowing through the DAG like a build system.

Task Lifecycle

pending → in_progress → completed
                      → deleted (permanently removed)

Tasks are created as pending. Mark in_progress before starting work, completed when done. deleted removes entirely — IDs never reset.

Dependency Management

• Bidirectional edges: addBlocks/addBlockedBy maintain both sides automatically
• Dependency warnings: cycles, self-dependencies, and references to non-existent tasks are stored but produce warnings in the tool response
• Display-time filtering: TaskList only shows non-completed blockers in [blocked by ...]
• Raw data preserved: TaskGet shows ALL edges, including completed blockers
• Cleanup on deletion: removing a task cleans up all edges pointing to it

Shared Task Lists

Set PI_TASK_LIST_ID to enable file-backed storage for agent team coordination:

PI_TASK_LIST_ID=my-project pi

Tasks persist at ~/.pi/tasks/my-project.json. Multiple sessions sharing the same ID read/write the same list with file locking (.lock files with stale-lock detection).

Without the env var, tasks are session-scoped (in-memory only).

/tasks Command

Interactive menu:

Tasks
├─ View all tasks (4)
├─ Create task
├─ Settings
└─ Clear completed (1)

• View all tasks — select a task to see details and take actions (start, complete, delete)
• Create task — input prompts for subject and description
• Settings — toggle auto-cascade (auto-execute unblocked agent tasks on completion)
• Clear completed — remove all completed tasks

Cross-extension Communication with @tintinweb/pi-subagents

pi-tasks communicates with @tintinweb/pi-subagents via pi's eventbus using a scoped request/reply RPC protocol. No shared global state — just events.

Presence Detection

Load order doesn't matter. Two handshake paths ensure detection regardless of which extension loads first:

1. Ping on init — pi-tasks emits subagents:rpc:ping with a unique requestId and listens for subagents:rpc:ping:reply:{requestId}. If pi-subagents is already loaded, it replies immediately.
2. Ready broadcast — pi-subagents emits subagents:ready when it initializes. If pi-tasks loaded first, it picks this up.

┌─────────────┐                    ┌──────────────────┐
│  pi-tasks   │                    │  pi-subagents    │
└──────┬──────┘                    └────────┬─────────┘
       │                                    │
       │──── subagents:rpc:ping ───────────▶│
       │◀─── subagents:rpc:ping:reply ──────│
       │                                    │
       │◀─── subagents:ready ───────────────│  (broadcast on init)
       │                                    │

Spawning Subagents

When TaskExecute runs, it sends a spawn RPC with a scoped reply channel:

pi-tasks                                pi-subagents
   │                                         │
   │── subagents:rpc:spawn ─────────────────▶│  { requestId, type, prompt, options }
   │◀─ subagents:rpc:spawn:reply:{reqId} ───│  { id }  (or { error })
   │                                         │

The returned id is stored in an in-memory agentTaskMap (agentId → taskId) for O(1) completion lookup. A 30-second timeout rejects the Promise if no reply arrives.

Lifecycle Events

pi-subagents emits lifecycle events that pi-tasks listens to:

Event	Payload	Action
subagents:completed	{ id, result? }	Mark task completed, trigger auto-cascade if enabled
subagents:failed	{ id, error?, status }	Revert task to pending, store error in metadata

Standalone Mode

If pi-subagents is not installed, everything works except TaskExecute, which returns a friendly error message. All core task tools (create, list, get, update, dependencies, widget, system-reminder injection) function independently.

Architecture

src/
├── index.ts            # Extension entry: 7 tools + /tasks command + widget + subagent integration
├── types.ts            # Task, TaskStatus, BackgroundProcess, SubagentBridge types
├── task-store.ts       # File-backed store with CRUD, dependencies, locking
├── process-tracker.ts  # Background process output buffering and stop
└── ui/
    └── task-widget.ts  # Persistent widget with status icons and spinner

Future Work

• Background Bash auto-task creation — Claude Code auto-creates tasks when Bash runs with run_in_background: true. Pi's bash tool currently lacks a run_in_background parameter (only command + timeout), so there's nothing to hook into. Once pi adds background execution support to its bash tool, we can use the tool_call event to detect it and auto-create tasks via TaskStore/ProcessTracker.

Development

npm install
npm run typecheck   # TypeScript validation
npm test            # Run unit tests (102 tests)

License

MIT — tintinweb