Creative Constraints MCP Server

@pipeworx/creative-constraints

Draws from an original, 162-card deck of domain-neutral creative constraints — each card is one imperative sentence an agent or a team can apply to any task (a product launch, an essay, an onboarding flow, a dinner), plus one sentence on why it helps. Meanings are returned separately from interpretation: the tool hands back what was drawn and the procedure used, and the calling agent decides what to do with it.

Part of Pipeworx — an MCP gateway connecting AI agents to 1863+ live data sources. This is an independent, unofficial integration — not affiliated with, endorsed by, or published by the upstream provider.

Part of the Pipeworx "chance" family — a shared seeded-RNG and session engine also used by dice-roller, tarot, i-ching and random-tables (see docs/chance-packs-plan.md).

Tools

• draw_constraint(count?, categories?, seed?, session_id?) — draws 1-10 cards, optionally restricted to one or more of the nine categories. Pass seed to reproduce an exact draw later (same seed + count + categories always returns the same cards); omit it for a fresh random draw, and the seed actually used is returned. Pass session_id from a previous response to continue a no-repeat session (draw-without-replacement across calls).
• list_constraint_categories() — lists the nine categories, each with its card count and one example title.
• get_constraint(id) — fetches one specific card by its id (e.g. "inversion_03").

Auth

Keyless. No upstream API, no third-party dependency.

Data sources

• Pipeworx — original creative-constraints deck. Every card's title, constraint sentence and rationale is written for this pack; there is no public-domain or commercial foundation behind it (unlike tarot's Rider–Waite–Smith tradition or i-ching's Legge translation).

The nine categories

perspective, limitation, medium, time, audience, inversion, scale, process, wildcard — 18 cards each, 162 total.

Sessions are hosted-only

draw_constraint's session_id support depends on the gateway's KV cache binding (injectCacheKv: true on this pack's manifest row). The published npm standalone has no such binding, so a session_id there (or from any caller without the gateway's cache) gets session_supported: false in the response and falls back to a plain seeded draw — fully reproducible by seed, just not draw-without-replacement across separate calls. Sessions expire after 24 hours of inactivity.

Reproducibility

Every draw is seeded. Omit seed for a fresh random draw (the seed used is always returned in meta.seed); pass that seed back, with the same count and categories, to reproduce the exact same cards. When continuing an existing session via session_id, the session keeps the category filter it was opened with — categories is ignored on that call.

Errors

An unknown category in categories is a loud error listing the valid set. An unknown id to get_constraint is a loud error with the id-naming convention. An expired or unknown session_id is a loud error telling you to omit it to start a new session.

Quick Start

Add to your MCP client (Claude Desktop, Cursor, Windsurf, etc.):

{
  "mcpServers": {
    "creative-constraints": {
      "url": "https://gateway.pipeworx.io/creative-constraints/mcp"
    }
  }
}

What this endpoint actually serves

tools/list at https://gateway.pipeworx.io/creative-constraints/mcp returns the tools in the table above plus the shared Pipeworx meta-tools — ask_pipeworx, discover_tools, search_within, remember/recall and the rest of the gateway-wide set. So the tool count you see is larger than this table: a single-pack endpoint currently lists roughly 30 shared tools alongside the pack's own. The connection's initialize response states its exact scope, and is the authoritative answer for a given day.

This is deliberate, not multiplexing by accident. The meta-tools are what let a scoped connection answer a question this pack does not cover — via ask_pipeworx, which routes across the whole catalog — without you adding a second MCP server. There is currently no way to mount a pack endpoint without them; if the extra schemas cost you more context than the routing is worth, connect to the full gateway once rather than to several pack endpoints.

Or connect to the full Pipeworx gateway to get every pack's tools listed directly, instead of just this one's:

{
  "mcpServers": {
    "pipeworx": {
      "url": "https://gateway.pipeworx.io/mcp"
    }
  }
}

Both URLs reach the same gateway and the same 1863+ data sources. The only difference is which pack's tools are listed directly; ask_pipeworx reaches all of them from either one.

No MCP client? Call it over HTTP

curl -X POST https://gateway.pipeworx.io/v1/tools/draw_constraint \
  -H 'Content-Type: application/json' \
  -d '{"categories":["inversion"],"count":3,"seed":"pipeworx-demo"}'

No account needed for the first calls. Inspect any tool: GET https://gateway.pipeworx.io/v1/tools/draw_constraint. Find one: POST https://gateway.pipeworx.io/v1/tools/search_packs with {"query":"..."}.

Run it from npm

@pipeworx/mcp-creative-constraints is a local stdio bridge to the Pipeworx gateway: your MCP client starts it with npx, and it forwards every call to the same https://gateway.pipeworx.io/creative-constraints/mcp endpoint shown above. It needs network access; there is no offline mode.

{
  "mcpServers": {
    "creative-constraints": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-creative-constraints"]
    }
  }
}

Without a key it calls anonymously, capped at 50 calls a day. A free account raises that to 200 a day: get a key at https://pipeworx.io/signup and add "env": { "PIPEWORX_API_KEY": "<your key>" } to the server entry. The key is sent as a Bearer token, the same way a hosted connection sends it, so calls are metered and billed exactly as they are there.

It lists only this pack's tools by default. Set PIPEWORX_META_TOOLS=1 to also list ask_pipeworx and the other gateway-wide tools.

Behind an HTTPS proxy: Node's built-in fetch does not read HTTPS_PROXY by default. Newer Node releases honour it when NODE_USE_ENV_PROXY=1 is set; check your Node version's documentation.

Using with ask_pipeworx

Instead of calling tools directly, you can ask questions in plain English — this works on the pack endpoint above as well as on the full gateway:

ask_pipeworx({ question: "your question about Creative Constraints data" })

The gateway picks the right tool and fills the arguments automatically.

More

• Docs and guides
• pipeworx.io

License

MIT