Task Graph MCP Server

Agent task workflows that actually work.

When you have AI agents working on complex tasks, things go wrong fast. Agents lose context, skip steps, forget to coordinate. Task Graph solves this with structured workflows: phases to guide work, prompts for automatic guidance, gates to enforce quality, and coordination primitives for multi-agent scenarios—all through the Model Context Protocol.

Why Task Graph?

The problem: You've got complex tasks that need structured execution. Maybe a single agent working through phases, or multiple agents coordinating in parallel. Without proper workflows, agents lose track, skip steps, and produce inconsistent results.

What you get:

• Structured workflows — Phases (explore, implement, review, test) guide agents through work. Transition prompts provide automatic guidance at each step.
• Quality gates — Require tests to pass, code to be committed, or reviews to complete before transitions. Enforce your standards automatically.
• Ready-to-use topologies — Pre-built workflows for solo work, parallel swarms, specialist relays, or hierarchical delegation. Start immediately, customize later.
• Configurable workflows — Define your own states, phases, prompts, and gates. Match your process, not ours.
• Multi-agent coordination — Advisory file locks, DAG dependencies, atomic claiming. No more conflicts or duplicate work.
• Token-efficient — Designed for LLM context limits. Compact queries, minimal round-trips, structured outputs.
• Built-in accounting — Track tokens, cost, and time per task. Know exactly what your agents are spending.
• Zero infrastructure — SQLite with WAL mode. No database server to run. Just point at a file.

Features

Feature	Description
Task Hierarchy	Unlimited nesting with parent/child relationships
DAG Dependencies	Typed edges (blocks, follows, contains) with cycle detection
Phases	Categorize work type (explore, implement, review, test, deploy)
Workflows	Named workflow topologies (solo, swarm, relay, hierarchical)
Transition Prompts	Automatic agent guidance on status/phase changes
Gates	Exit requirements for status/phase transitions
Atomic Claiming	Strict locking with limits and tag-based routing
File Coordination	Advisory locks with reasons and change polling
Cost Tracking	Token usage and USD cost per task
Time Tracking	Automatic accumulation from state transitions
Live Status	Real-time "current thought" visible to other agents
Full-text Search	FTS5-powered search across tasks and attachments
Attachments	Inline content, file references, or media storage
Agent Feedback	Inter-agent communication with categorized feedback (conditional on config)
Dynamic Overlays	Runtime workflow customization via add/remove overlay tools

Quick Start

# Install
cargo install task-graph-mcp

# Add to your MCP client (Claude Code, etc.)

{
  "mcpServers": {
    "task-graph": {
      "command": "task-graph-mcp"
    }
  }
}

# Agent workflow (worker_id auto-generated if omitted)
connect(workflow="swarm", tags=["code"])                 → "bright-lunar-swift-fox"
list_tasks(ready=true, agent="bright-lunar-swift-fox")   → claimable work
claim(worker_id="bright-lunar-swift-fox", task="add-auth")  → you own it
update(..., phase="implement")                           → enter implementation phase
thinking(agent="bright-lunar-swift-fox", thought="Adding JWT...")  → visible to others
update(worker_id="bright-lunar-swift-fox", task="add-auth",
       status="completed",
       attachments=[{type:"commit", content:"abc123"}])  → done

Installation

From crates.io (Recommended)

cargo install task-graph-mcp

Pre-built Binaries

Download the latest release for your platform from GitHub Releases:

Platform	Download
Linux (x64)	task-graph-mcp-x86_64-unknown-linux-gnu.tar.gz
macOS (Intel)	task-graph-mcp-x86_64-apple-darwin.tar.gz
macOS (Apple Silicon)	task-graph-mcp-aarch64-apple-darwin.tar.gz
Windows (x64)	task-graph-mcp-x86_64-pc-windows-msvc.zip

Extract and place the binary in your PATH.

From Source

git clone https://github.com/Oortonaut/task-graph-mcp.git
cd task-graph-mcp
cargo build --release

The binary will be at target/release/task-graph-mcp.

Usage

As an MCP Server

Add to your MCP client configuration:

{
  "mcpServers": {
    "task-graph": {
      "command": "task-graph-mcp",
      "args": []
    }
  }
}

CLI Options

task-graph-mcp [OPTIONS]

Options:
  -c, --config <FILE>     Path to configuration file
  -d, --database <FILE>   Path to database file (overrides config)
  -v, --verbose           Enable verbose logging
  -h, --help              Print help
  -V, --version           Print version

Configuration

Full reference: See docs/CONFIGURATION.md for complete configuration documentation including workflows, prompts, gates, roles, and tags.

Create .task-graph/config.yaml:

server:
  db_path: .task-graph/tasks.db
  media_dir: .task-graph/media  # Directory for file attachments
  skills_dir: .task-graph/skills  # Custom skill overrides
  stale_timeout_seconds: 900
  default_format: json  # or markdown

paths:
  style: relative  # or project_prefixed

auto_advance:
  enabled: false        # Auto-transition unblocked tasks
  target_state: ready   # Target state (requires custom state in states config)

States Configuration

Task states are configurable. Default states: pending, working, completed, failed, cancelled.

To add a ready state for auto-advance:

states:
  initial: pending
  disconnect_state: pending  # State for tasks when owner disconnects (must be untimed)
  blocking_states: [pending, working]
  definitions:
    pending:
      exits: [ready, working, cancelled]
    ready:
      exits: [working, cancelled]
    working:
      exits: [completed, failed, pending]
      timed: true    # Time in this state counts toward time_actual_ms
    completed:
      exits: []
    failed:
      exits: [pending]
    cancelled:
      exits: []

auto_advance:
  enabled: true
  target_state: ready

See SCHEMA.md for full documentation on state definitions.

Dependencies Configuration

Dependency types define how tasks relate to each other. Default types: blocks, follows, contains, duplicate, see-also, relates-to.

dependencies:
  definitions:
    blocks:
      display: horizontal  # Same-level relationship
      blocks: start        # Blocks claiming the dependent task
    follows:
      display: horizontal
      blocks: start
    contains:
      display: vertical    # Parent-child relationship
      blocks: completion   # Blocks completing the parent
    duplicate:
      display: horizontal
      blocks: none         # Informational only
    see-also:
      display: horizontal
      blocks: none
    relates-to:
      display: horizontal
      blocks: none

Property	Values	Description
display	horizontal, vertical	Visual relationship (same-level vs parent-child)
blocks	none, start, completion	What the dependency blocks

Attachments Configuration

Preconfigured attachment keys provide default MIME types and modes, reducing boilerplate when attaching common content types.

attachments:
  unknown_key: warn  # allow | warn (default) | reject
  definitions:
    commit:
      mime: text/git.hash
      mode: append
    checkin:
      mime: text/p4.changelist
      mode: append
    meta:
      mime: application/json
      mode: replace
    note:
      mime: text/plain
      mode: append

Property	Values	Description
unknown_key	allow, warn, reject	Behavior for undefined attachment keys
definitions.<key>.mime	MIME type string	Default MIME type for this key
definitions.<key>.mode	append, replace	Default mode (append keeps existing, replace overwrites)

Built-in defaults:

Key	MIME Type	Mode	Use Case
commit	text/git.hash	append	Git commit hashes
checkin	text/p4.changelist	append	Perforce changelists
changelist	text/plain	append	Files changed
meta	application/json	replace	Structured metadata
note	text/plain	append	General notes
log	text/plain	append	Log output
error	text/plain	append	Error messages
output	text/plain	append	Command/tool output
diff	text/x-diff	append	Patches and diffs
plan	text/markdown	replace	Plans and specs
result	application/json	replace	Structured results
context	text/plain	replace	Current context/state

Usage:

# MIME and mode auto-filled from config:
attach(task="123", name="commit", content="abc1234")
# → mime=text/git.hash, mode=append

attach(task="123", name="meta", content='{"v":1}')
# → mime=application/json, mode=replace (overwrites existing meta)

# Explicit values override defaults:
attach(task="123", name="commit", mime="text/plain", content="override")

Environment variables:

• TASK_GRAPH_CONFIG_PATH: Path to configuration file (takes precedence over .task-graph/config.yaml)
• TASK_GRAPH_DB_PATH: Database file path (fallback if no config file)
• TASK_GRAPH_MEDIA_DIR: Media directory for file attachments (fallback if no config file)
• TASK_GRAPH_LOG_DIR: Log directory path (fallback if no config file)

MCP Tools

Worker Management

Tool	Description
connect(worker_id?, tags?, workflow?, force?, db_path?, media_dir?, log_dir?, config_path?, overlays?: str[])	Register a worker. Optional workflow selects named workflow (solo, swarm, relay, hierarchical). Returns worker_id and active paths.
disconnect(worker_id: worker_str, final_status?: status_str = "pending")	Unregister worker and release all claims/locks.
list_agents(tags?: str[], file?: filename, task?: task_str, depth?: int, stale_timeout?: int)	List connected workers with filters.
cleanup_stale(timeout?: int, final_status?: status_str)	Evict stale workers and release their claims.
add_overlay(worker_id: str, overlay: str)	Add a dynamic workflow overlay to a connected worker.
remove_overlay(worker_id: str, overlay: str)	Remove a workflow overlay from a connected worker.

Task CRUD

Tool	Description
create(description: str, id?: task_str, parent?: task_str, priority?: int = 5, points?: int, time_estimate_ms?: int, tags?: str[])	Create a task. Priority 0-10 (higher = more important).
create_tree(tree, parent?, child_type?, sibling_type?)	Create nested task tree. child_type (default: "contains") for parent→child deps, sibling_type for sibling deps.
get(task: task_str)	Get task by ID with attachment metadata and counts.
list_tasks(status?: status_str[], ready?: bool, blocked?: bool, claimed?: bool, owner?: worker_str, parent?: task_str, recursive?: bool, agent?: worker_str, tags_any?: str[], tags_all?: str[], sort_by?: str, sort_order?: str, limit?: int, offset?: int)	Query tasks with filters. Use ready=true for claimable tasks.
update(worker_id: worker_str, task: task_str, status?: status_str, phase?: str, assignee?: worker_str, title?: str, description?: str, priority?: int, points?: int, tags?: str[], needed_tags?: str[], wanted_tags?: str[], time_estimate_ms?: int, reason?: str, force?: bool, attachments?: object[])	Update task. Status/phase changes auto-manage ownership and trigger prompts. Include attachments to record commits/changelists.
delete(worker_id: worker_str, task: task_str, cascade?: bool, reason?: str, obliterate?: bool, force?: bool)	Delete task. Soft delete by default; obliterate=true for permanent.
scan(task: task_str, before?: int, after?: int, above?: int, below?: int)	Scan task graph in multiple directions. Depth: 0=none, N=levels, -1=all.
search(query: str, limit?: int = 20, include_attachments?: bool, status_filter?: status_str)	FTS5 search. Supports phrases, prefix*, AND/OR/NOT, title:word.
rename(worker_id: worker_str, task: task_str, new_id: task_str)	Atomically rename a task ID across all referencing tables.

Task Claiming

Tool	Description
claim(worker_id: worker_str, task: task_str, force?: bool)	Claim a task. Fails if deps unsatisfied, at limit, or lacks tags. Use force to steal.

Note: Release via update(status="pending"). Complete via update(status="completed"). Status changes auto-manage ownership.

Dependencies

Tool	Description
link(from: task_str|task_str[], to: task_str|task_str[], type?: dep_str = "blocks")	Create dependencies. Types: blocks, follows, contains, duplicate, see-also, relates-to.
unlink(from: task_str|"*", to: task_str|"*", type?: dep_str)	Remove dependencies. Use * as wildcard.
relink(prev_from: task_str[], prev_to: task_str[], from: task_str[], to: task_str[], type?: dep_str = "contains")	Atomically move dependencies (unlink then link).

Tracking

Tool	Description
thinking(worker_id: worker_str, thought: str, tasks?: task_str[])	Broadcast live status. Visible to other workers. Refreshes heartbeat.
task_history(task: task_str, states?: status_str[])	Get status transition history with time tracking.
project_history(from?: datetime_str, to?: datetime_str, states?: status_str[], limit?: int = 100)	Project-wide history with date range filters.
log_metrics(worker_id: worker_str, task: task_str, cost_usd?: float, values?: int[8])	Log metrics (aggregated).
get_metrics(task: task_str|task_str[])	Get metrics for task(s).
give_feedback(message: str, category?: str, sentiment?: str, agent_id?: str, tool_name?: str, task_id?: str)	Record feedback about tools, workflows, or UX. Enabled by default; rejects writes past size limit (default: 1MB).
list_feedback()	Read the feedback markdown file.

File Coordination

Tool	Description
mark_file(worker_id: worker_str, file: filename|filename[], task?: task_str, reason?: str)	Mark file(s) to signal intent. Advisory, non-blocking.
unmark_file(worker_id: worker_str, file?: filename|filename[]|"*", task?: task_str, reason?: str)	Remove marks. Use * for all.
list_marks(files?: filename[], worker_id?: worker_str, task?: task_str)	Get current file marks.
mark_updates(worker_id: worker_str)	Poll for mark changes since last call.

Attachments

Tool	Description
attach(task: task_str|task_str[], name: str, content?: str, mime?: mime_str, file?: filename, store_as_file?: bool, mode?: str)	Add attachment. Use file for reference, store_as_file for media storage.
attachments(task: task_str, name?: str, mime?: mime_str)	Get attachment metadata. Glob patterns supported for name.
detach(worker_id: worker_str, task: task_str, name: str, delete_file?: bool)	Delete attachment by name.

Advanced

Tool	Description
check_gates(task: task_str)	Check gate requirements before status/phase transition. Returns unsatisfied gates with pass/warn/fail status.
get_advisory(topic?: str, task?: task_str, worker_id?: worker_str)	Get governance advisory guidance. Without topic: lists all topics. With topic: returns full advisory content with template expansion.
query(sql: str, params?: str[], limit?: int = 100, format?: str)	Execute read-only SQL. SELECT only. Requires permission.
get_schema(table?: str, include_sql?: bool)	Get database schema. Returns table names, columns, types, and foreign keys.
get_prompts(status?: str, phase?: str, task?: task_str, worker_id?: worker_str)	Get workflow prompts. Without params: lists triggers. With status/phase: returns expanded prompts for that transition.
list_workflows()	List available workflow configurations (solo, swarm, relay, hierarchical, etc.).
list_skills()	List available bundled skills with descriptions.
get_skill(name: str)	Get full content of a bundled skill.

MCP Resources

URI	Description
query://tasks/all	Full task graph with dependencies
query://tasks/ready	Tasks ready to claim
query://tasks/blocked	Tasks blocked by dependencies
query://tasks/claimed	All claimed tasks
query://tasks/agent/{id}	Tasks owned by an agent
query://tasks/tree/{id}	Task with all descendants
query://files/marks	All file marks
query://agents/all	Registered agents
query://stats/summary	Aggregate statistics
config://current	All configuration in one response
config://states	Task state definitions
config://phases	Phase definitions
config://dependencies	Dependency type definitions
config://tags	Tag definitions
docs://index	List all available documentation files
docs://search/{query}	Full-text search across documentation
docs://skills/list	List available skills
docs://skills/{name}	Get specific skill content
docs://workflows/list	List available workflows
docs://workflows/{name}	Get workflow details
docs://overlays/list	List available overlays
docs://overlays/{name}	Get overlay details
docs://{path}	Specific documentation file content

Task Tree Structure

Create hierarchical tasks with create_tree:

{
  "tree": {
    "title": "Implement auth",
    "children": [
      { "title": "Design schema" },
      { "title": "Write migrations" },
      { "title": "Implement endpoints", "children": [
        { "title": "Login endpoint" },
        { "title": "Logout endpoint" },
        { "title": "Refresh endpoint" }
      ]},
      { "title": "Write tests" }
    ]
  },
  "sibling_type": "follows"
}

Tree Node Fields

Field	Description
title	Task title (required for new tasks)
description	Task description
id	Custom task ID (UUID7 generated if omitted)
ref	Reference existing task by ID (other fields ignored when set)
priority	Priority 0-10 (default 5)
points	Story points / complexity estimate
time_estimate_ms	Estimated duration in milliseconds
tags	Categorization tags for the task
needed_tags	Agent must have ALL of these tags to claim (AND)
wanted_tags	Agent must have AT LEAST ONE of these tags to claim (OR)
children	Nested child nodes

Top-Level Parameters

Parameter	Default	Description
tree	required	Root node of the task tree
parent	null	Attach tree root to existing parent task
child_type	"contains"	Dependency type from parent to children
sibling_type	null	Dependency type between siblings ("follows" for sequential, null for parallel)

Referencing Existing Tasks

Use ref to integrate existing tasks into a tree structure:

{
  "tree": {
    "title": "Sprint 5",
    "children": [
      { "title": "New feature" },
      { "ref": "existing-task-id" },
      { "title": "Another task" }
    ]
  },
  "sibling_type": "follows"
}

Tag-Based Affinity

Workers declare capabilities via tags when connecting. Tasks can require specific tags to control which workers can claim them.

Example tag categories:

• Model capabilities: image-in, audio-out, video-in, code, bulk
• Access levels: prod-access, admin, external
• Specializations: rust, python, frontend, database

Note: Roles like coordinator/reviewer/deployer are better represented using phases.

Task requirements:

• needed_tags (AND): Agent must have ALL of these
• wanted_tags (OR): Agent must have AT LEAST ONE

{
  "title": "Analyze screenshot and generate code",
  "needed_tags": ["image-in", "code"],
  "wanted_tags": ["bulk"]
}

{
  "title": "Deploy to production",
  "phase": "deploy",
  "needed_tags": ["prod-access"],
  "wanted_tags": ["aws", "gcp"]
}

Workflows and Phases

Phases

Tasks can have a phase to categorize the type of work being performed:

{
  "title": "Add authentication",
  "phase": "implement"
}

Built-in phases: explore, implement, review, test, security, deploy, triage, diagnose, design, plan, doc, integrate, monitor, optimize

Phases enable:

• Transition prompts — Automatic guidance when entering/exiting phases
• Gates — Requirements that must be satisfied before phase transitions
• Role-based routing — In relay workflows, specialists own specific phases

Named Workflows

Pre-built workflow topologies optimize for different coordination patterns:

Workflow	Description	Best For
solo	Single agent, full autonomy	Simple tasks, prototyping
swarm	Parallel generalists, pull-based	High throughput, independent tasks
relay	Sequential specialists, handoffs	Complex tasks, domain expertise
hierarchical	Lead/worker delegation	Large projects, team coordination
push	Push-based task distribution topology	Centralized assignment, load balancing
kanban	Board-style task management with WIP limits	Continuous flow, visual tracking
sprint	Time-boxed iteration planning	Scrum teams, fixed cadence

Select a workflow on connect:

connect(worker_id="agent-1", workflow="swarm")

Each workflow provides tailored prompts and coordination guidance. See WORKFLOW_TOPOLOGIES.md for detailed patterns.

Transition Prompts

Agents receive automatic guidance when status or phase changes:

# workflows.yaml
states:
  working:
    prompts:
      enter: |
        You are now working on this task.
        From {{current_status}} you can transition to: {{valid_exits}}
      exit: |
        Before leaving:
        - [ ] Attach results
        - [ ] Log costs

Prompts support template variables: {{current_status}}, {{valid_exits}}, {{current_phase}}, {{valid_phases}}

Gates

Gates are requirements that must be satisfied before status or phase transitions:

gates:
  status:working:
    - type: gate/tests
      enforcement: warn
      description: "Tests must pass"

Satisfy a gate by attaching evidence:

attach(task="123", type="gate/tests", content="All tests passing")

Enforcement levels: allow (advisory), warn (blocks unless force=true), reject (hard block)

File Coordination

Agents can coordinate file edits using advisory marks with change tracking:

Worker A: connect() -> "worker-a"
Worker A: mark_file("worker-a", "src/main.rs", "refactoring")
Worker B: connect() -> "worker-b"
Worker B: mark_updates("worker-b") -> sees worker-a's mark
Worker A: unmark_file("worker-a", "src/main.rs", "ready for review")
Worker B: mark_updates("worker-b") -> sees removal with reason
Worker B: mark_file("worker-b", "src/main.rs", "adding tests")

Architecture

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│  Agent A    │     │  Agent B    │     │  Agent C    │
│  (Claude)   │     │  (GPT-4)    │     │  (Worker)   │
└──────┬──────┘     └──────┬──────┘     └──────┬──────┘
       │ stdio             │ stdio             │ stdio
       ▼                   ▼                   ▼
┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│ task-graph  │     │ task-graph  │     │ task-graph  │
│    MCP      │     │    MCP      │     │    MCP      │
└──────┬──────┘     └──────┬──────┘     └──────┬──────┘
       │                   │                   │
       └───────────────────┼───────────────────┘
                           ▼
                  ┌─────────────────┐
                  │   SQLite + WAL  │
                  │  .task-graph/   │
                  │    tasks.db     │
                  └─────────────────┘

• Transport: Stdio — each worker spawns its own server process
• Database: SQLite with WAL mode for concurrent access across processes
• Deployment: Single binary, no external dependencies, works offline

Compared to Alternatives

	Task Graph	Linear task lists	Custom databases
Workflow phases	✓ Built-in with prompts	✗ Manual tracking	DIY
Quality gates	✓ Configurable enforcement	✗	DIY
Multi-agent safe	✓ Atomic claims, file locks	✗ Race conditions	Maybe, DIY
Dependency tracking	✓ DAG with cycle detection	✗ Manual ordering	DIY
MCP native	✓ First-class	✗ Wrapper needed	✗ Wrapper needed
Token accounting	✓ Built-in	✗	DIY
Setup required	None	None	Database server

Documentation

Document	Description
CONFIGURATION.md	Complete configuration reference (config.yaml, workflows, prompts, gates, tags)
SCHEMA.md	Database schema and state machine documentation
DESIGN.md	Architecture and design decisions
WORKFLOW_TOPOLOGIES.md	Multi-agent workflow patterns (solo, swarm, relay, hierarchical)
EXPORT_IMPORT.md	Data export and import functionality
PROCESSES.md	Release process, changelog maintenance
GATES.md	Workflow gate conditions and enforcement
METRICS.md	Experiment metrics definitions and SQL examples

License

Apache 2.0

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Built for AI agents that need structured workflows and reliable coordination.