fusion/packages/cli/skill/fusion/references/extension-tools.md

Fusion Pi Extension Tools

All tools are registered via the pi extension. They are available in any pi agent session when the Fusion extension is installed.

Naming contract: all externally exposed Fusion extension tools are fn_* (for example fn_task_create). Engine runtime sessions also inject additional fn_* tools (for example fn_review_step, fn_spawn_agent, fn_task_document_write) that are separate from this extension surface and documented in engine-tools.md.

Task Tools

fn_task_create

Create a new task on the Fusion task board. The task enters the triage column where the AI triage agent will specify it into a full prompt with steps, file scope, and acceptance criteria.

Parameter	Type	Required	Description
description	string	✓	What needs to be done — be descriptive
depends	array	—	Task IDs this depends on (e.g. ['FN-001', 'FN-002'])
agentId	string	—	Agent ID to assign this task to (e.g. 'agent-abc123')

fn_task_update

Update fields on an existing task. Supports modifying the title, description, dependencies, and assigned agent after task creation.

Parameter	Type	Required	Description
id	string	✓	Task ID (e.g. FN-001)
title	string	—	New task title
description	string	—	New task description
depends	array	—	New dependency list — replaces existing dependencies (e.g. ['FN-001', 'FN-002'])
agentId	union	—	Agent ID to assign this task to, or null to clear (e.g. 'agent-abc123')

fn_task_list

List all tasks on the Fusion board, grouped by column.

Parameter	Type	Required	Description
column	string(enum)	—	Filter to a specific column
limit	number	—	Max tasks to show per column (default: 10)

fn_task_show

Show full details for a task including steps, progress, and log entries.

Parameter	Type	Required	Description
id	string	✓	Task ID (e.g. FN-001)

fn_task_attach

Attach a file to a task. Supports images (png, jpg, gif, webp) and text files (txt, log, json, yaml, yml, toml, csv, xml).

Parameter	Type	Required	Description
id	string	✓	Task ID (e.g. FN-001)
path	string	✓	Path to the file to attach

fn_task_pause

Pause a task — stops all automated agent and scheduler interaction for this task.

Parameter	Type	Required	Description
id	string	✓	Task ID (e.g. FN-001)

fn_task_unpause

Unpause a task — resumes automated agent and scheduler interaction.

Parameter	Type	Required	Description
id	string	✓	Task ID (e.g. FN-001)

fn_task_retry

Retry a failed task — clears the error state and moves it back to the todo column for re-execution.

Parameter	Type	Required	Description
id	string	✓	Task ID to retry (e.g. FN-001). Must be in 'failed' state.

fn_task_duplicate

Duplicate an existing task, creating a fresh copy in triage. Copies the title and description but resets all execution state. The AI triage agent will re-specify the new task.

Parameter	Type	Required	Description
id	string	✓	Source task ID to duplicate (e.g. FN-001)

fn_task_refine

Request a refinement of a completed or in-review task. Creates a new follow-up task in triage that references the original task as a dependency. Use this when a done or in-review task needs additional work, improvements, or follow-up changes.

Parameter	Type	Required	Description
id	string	✓	Task ID to refine (e.g. FN-001). Must be in 'done' or 'in-review' column.
feedback	string	✓	Description of what needs to be refined or improved

fn_task_archive

Archive a done task (move from done → archived). Archived tasks are preserved for historical reference but moved out of the main board view.

Parameter	Type	Required	Description
id	string	✓	Task ID to archive (e.g. FN-001). Must be in 'done' column.

fn_task_unarchive

Unarchive an archived task (move from archived → done). Restores the task to the done column.

Parameter	Type	Required	Description
id	string	✓	Task ID to unarchive (e.g. FN-001). Must be in 'archived' column.

fn_task_delete

Permanently delete a task from the Fusion board. Tasks are deleted immediately and cannot be recovered.

Parameter	Type	Required	Description
id	string	✓	Task ID to delete (e.g. FN-001)

fn_task_plan

Create a task via AI-guided planning mode — interactive conversation to refine your idea into a well-specified task.

Parameter	Type	Required	Description
description	string	—	Initial plan description (optional) — the AI will ask clarifying questions if not provided

GitHub Tools

fn_task_import_github

Import GitHub issues as Fusion tasks. Fetches open issues from a repository and creates tasks in the triage column. Each task includes the issue title and body with a link to the source issue.

Parameter	Type	Required	Description
ownerRepo	string	✓	Repository in owner/repo format (e.g., 'dustinbyrne/fusion')
limit	number	—	Max issues to import (default: 30, max: 100)
labels	array	—	Label names to filter by

fn_task_import_github_issue

Import a specific GitHub issue as a Fusion task. Fetches the issue by number and creates a single task in the triage column with the issue title and body.

Parameter	Type	Required	Description
owner	string	✓	Repository owner (e.g., 'dustinbyrne')
repo	string	✓	Repository name (e.g., 'fusion')
issueNumber	number	✓	GitHub issue number to import

fn_task_browse_github_issues

List open GitHub issues from a repository to browse before importing. Returns issue numbers, titles, and URLs for selection. Use with fn_task_import_github_issue to import specific issues by number.

Parameter	Type	Required	Description
owner	string	✓	Repository owner (e.g., 'dustinbyrne')
repo	string	✓	Repository name (e.g., 'fusion')
limit	number	—	Max issues to show (default: 30, max: 100)
labels	array	—	Label names to filter by

Mission Tools

fn_mission_create

Create a new mission — a high-level objective that can span multiple milestones. Missions contain milestones that break down work into phases.

Parameter	Type	Required	Description
title	string	✓	Mission title — brief but descriptive
description	string	—	Detailed mission objectives and context
autoAdvance	boolean	—	Automatically activate the next pending slice when the current slice completes

fn_mission_list

List all missions with their current status.

No parameters.

fn_mission_show

Show mission details with full hierarchy: milestones → slices → features.

Parameter	Type	Required	Description
id	string	✓	Mission ID (e.g., M-001)

fn_mission_delete

Delete a mission and all its milestones, slices, and features. Cannot be undone.

Parameter	Type	Required	Description
id	string	✓	Mission ID to delete (e.g., M-001)

fn_milestone_add

Add a milestone to a mission. Milestones represent phases of work.

Parameter	Type	Required	Description
missionId	string	✓	Parent mission ID (e.g., M-001)
title	string	✓	Milestone title
description	string	—	Milestone description

fn_slice_add

Add a slice to a milestone. Slices are work units that can be activated for implementation.

Parameter	Type	Required	Description
milestoneId	string	✓	Parent milestone ID (e.g., MS-001)
title	string	✓	Slice title
description	string	—	Slice description

fn_feature_add

Add a feature to a slice. Features are deliverables that can be linked to tasks.

Parameter	Type	Required	Description
sliceId	string	✓	Parent slice ID (e.g., SL-001)
title	string	✓	Feature title
description	string	—	Feature description
acceptanceCriteria	string	—	Acceptance criteria for completing the feature

fn_slice_activate

Activate a pending slice for implementation. Sets status to 'active' and enables task linking for its features.

Parameter	Type	Required	Description
id	string	✓	Slice ID to activate (e.g., SL-001)

fn_feature_link_task

Link a feature to a fn task for implementation. Updates the feature status to 'triaged' and associates it with the task.

Parameter	Type	Required	Description
featureId	string	✓	Feature ID to link (e.g., F-001)
taskId	string	✓	Task ID to link to (e.g., FN-001)

Agent Tools

fn_agent_stop

Stop a running agent — pauses its execution. Transitions the agent from running/active to paused state.

Parameter	Type	Required	Description
id	string	✓	Agent ID to stop (e.g., agent-abc123)

fn_agent_start

Start a stopped agent — resumes its execution. Transitions the agent from paused to active state.

Parameter	Type	Required	Description
id	string	✓	Agent ID to start (e.g., agent-abc123)

Skills Tools

fn_skills_search

Search the skills.sh directory for agent skills. Returns matching skills with names, sources (owner/repo), install counts, and install commands. Use fn_skills_install to install a selected skill.

Parameter	Type	Required	Description
query	string	✓	Search query — framework name, technology, or capability (e.g., 'react', 'firebase', 'testing', 'docker')
limit	number	—	Max results to return (default: 10, max: 50)

fn_skills_install

Install an agent skill from skills.sh into the current project. Downloads skill files into the project's skill directories (.fusion/skills/, legacy .pi/skills/, .agents/skills/). The skill becomes available to AI agents in subsequent sessions.

Parameter	Type	Required	Description
source	string	✓	GitHub source in owner/repo format (e.g., 'firebase/agent-skills')
skill	string	—	Specific skill name to install (e.g., 'firebase-basics'). Omit to install all skills from the source.

Dashboard Command

/fn

Start or stop the Fusion dashboard from within a pi session.

Command	Description
/fn	Start dashboard on port 4040
/fn 8080	Start on custom port
/fn stop	Stop dashboard
/fn status	Check if running