Ganty MCP

Ganty is a Gantt chart SaaS with a built-in Model Context Protocol (MCP) server that lets AI clients like Claude Desktop and Claude Code drive your projects in natural language — and computes critical paths and shift-impact server-side rather than asking the LLM to do math.

Status: v1.0.0 — production endpoint at https://ganty.app/api/mcp (Streamable HTTP) Free on every Ganty plan including Free.

What makes this different

Most MCP servers expose CRUD over an existing API. Ganty's also exposes calculation tools that compute on the server and return JSON — so the LLM never has to reason about dates, dependencies, or critical paths.

get_critical_path — forward/backward-pass CPM with progress-aware remaining duration. Returns the critical path tasks in order, per-task earliest/latest start/finish, slack, projected end date. Detects cycles before computing and returns error: 'cyclic_dependency' instead of hanging or guessing.
reschedule_and_propagate — simulate or commit a task shift. Default mode is dry_run (no DB writes). Push-only cascade respects pinned tasks (anything at progress=100 or in pinned_task_ids) and reports conflicts instead of overwriting. commit mode wraps everything in an all-or-nothing transaction.

Quick start

Issue an MCP token in Ganty: dashboard → Settings → MCP Integration → "Issue new token".

Configure Claude Desktop (claude_desktop_config.json) or Claude Code (.mcp.json at project root):

{
  "mcpServers": {
    "ganty": {
      "url": "https://ganty.app/api/mcp",
      "headers": { "Authorization": "Bearer YOUR_TOKEN" }
    }
  }
}

Restart Claude and try a prompt:
- "List my Ganty projects"
- "What's the critical path for the e-commerce rebuild project?"
- "If I push the payments task by +3 days, when does release ship?"

Full setup walk-through: https://ganty.app/guide/mcp-integration

Tools

Read tools (visible to read-only and write tokens)

Tool	Description
`list_workspaces`	Workspaces the token's user belongs to
`list_projects`	Projects in a workspace
`list_tasks`	Tasks in a project (filter by name/status/assignee)
`get_task`	Single task with assignees + dependencies
`list_milestones`	Milestones in a project
`get_critical_path`	Server-side CPM with slack and total duration

Write tools (write-scope tokens only)

Tool	Description
`create_project`, `delete_project`	Project lifecycle
`create_task`, `update_task`, `delete_task`	Task lifecycle
`set_task_progress`	Update task progress (auto-sets status)
`add_dependency`	Finish-to-Start dependency between two tasks
`create_milestone`	Add a milestone
`reschedule_and_propagate`	Shift a task, cascade through dependencies, dry-run or commit

reschedule_and_propagate is classified as a write tool even in dry_run mode (it shares the same compute path as commit and we don't want read-only tokens running unlimited simulations).

v1 scope and limitations

We prefer explicit non-support over silent wrong answers. Every response from the calculation tools includes a limitations array.

Dependency types: Finish-to-Start only (Ganty's schema doesn't model SS/FF/SF)
Calendar: calendar days by default; business_days: true skips Sat/Sun only (no holiday table)
No resource calendars in v1
Multi-period tasks (extraSegments) are ignored in v1; calculations use only the main start/end of each task
Pinned tasks: progress=100 automatically pinned; supply pinned_task_ids for additional pins
Push-only cascade: successors are pushed back when required, never pulled forward

Architecture

Transport: Streamable HTTP (JSON-RPC 2.0 over HTTP POST) — https://ganty.app/api/mcp
Auth: Bearer tokens (gnty_...) issued from the Ganty dashboard. Tokens are scoped read or write.
Rate limits: 120 req/min for read, 30 req/min for write (per token)
Audit logging: every write call is logged with action, actor, IP, and arg summary
Atomicity: reschedule_and_propagate commit mode is wrapped in a Prisma transaction; conflicts abort without writes

The calculation logic lives in pure TypeScript functions backed by 28 golden tests asserting concrete dates and day counts (linear chain shifts, diamond merges, cycle detection within 2 seconds, progress-aware remaining duration, hand-calculated CPM with slack, business-day mode, lag-day handling, push-only cascade).

License

MIT for this documentation repository. The Ganty server itself is a hosted SaaS; the MCP endpoint is a feature of every Ganty workspace.