Formhaus

io.github.ignsmPublished by GitHub account ignsmv0.6.3Updated Nov 1, 2026

Validate Formhaus form definitions and simulate multi-step paths against the real engine.

VerifiedSTDIODesktop onlyProductivity & WorkflowDeveloper Tools

Overview

AI-generated overview

Local MCP server that lets an assistant validate Formhaus form definitions, apply safe fixes and simulate multi-step paths, plus publish and manage forms in…

What you can do
  • Validate form definitions and get issues with JSON pointers, hints and suggested patches
  • Apply safe fixes automatically and re-check the remaining issues
  • Simulate multi-step paths with answers, next/back/skip actions and overlays, returning visible fields, errors and submit values
  • Look up engine capabilities, generate translation overlay templates and load bundled example definitions
  • Publish forms and list forms, read submissions, update settings and read or reveal webhook details in Formhaus Cloud
When to use it
Useful when building or debugging Formhaus forms and you want an assistant to check definitions against the real engine, test branching paths, or prepare translations before shipping. Also relevant if you want the assistant to publish forms and inspect submissions through Formhaus Cloud.
Requirements
Runs locally over stdio via npx and needs Node 22.12 or later. Validation, fixing, simulation, capabilities, translation and examples work offline with no account or key. Cloud tools need FORMHAUS_API_KEY in the server's own environment (not the project .env); an account key reaches all forms, an agent key only the forms it created. FORMHAUS_API_BASE can override the API URL.
Before you install
Cloud tools send data to api.formhaus.dev, and publish_form creates live forms. reveal_webhook_secret returns a full webhook secret and is marked sensitive and non-read-only; whether the client asks first depends on its permission settings. update_form_settings changes live form settings. Keep data in your own backend and do not publish without user consent.

Installation

In SourceWeft

  1. Open Formhaus in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

@formhaus/mcp

[formhaus-dev/formhaus MCP server]

MCP server that lets AI agents check Formhaus form definitions against the real @formhaus/core engine. Runs over stdio. Requires Node 22.12 or later. The checks need no account or key.

validate_definition, fix_definition, simulate_path, translation_template, capabilities and example_definitions run offline. The other tools publish forms, read submissions and manage settings in Formhaus Cloud. If the app has its own backend, keep the data there and don't publish without the user's consent.

Setup

Claude Code plugin, with the Formhaus skills:

bash
claude plugin marketplace add formhaus-dev/formhausclaude plugin install formhaus@formhaus

Inside a Claude Code session, /plugin marketplace add formhaus-dev/formhaus and /plugin install formhaus@formhaus do the same after a confirmation prompt.

Claude Code, server only:

bash
claude mcp add formhaus -- npx -y @formhaus/mcp

Claude Desktop (claude_desktop_config.json) and Cursor (.cursor/mcp.json):

json
{  "mcpServers": {    "formhaus": {      "command": "npx",      "args": ["-y", "@formhaus/mcp"]    }  }}

Tools

ToolInputOutput
validate_definitiondefinition (object or JSON string){ valid, issues }. Each issue has code, severity, a JSON pointer path, message, hint and, when a repair is known, fixes ({ title, safe, patch } with an RFC 6902 JSON Patch)
fix_definitiondefinition (object or JSON string){ definition, applied, valid, issues }: the definition with every safe fix applied, the fixes applied and the issues left
simulate_pathdefinition, answers, optional actions (next, back, skip) and overlayActive step path with visible fields, action trace, validation ({ valid, issues }), field errors, wouldSubmit, submitValues. Group item fields appear as paths such as participants.0.email
capabilitiesnoneField types, sections, repeatable groups, field props, validation rules, condition operators, step and route semantics, translation catalogs, keys and overlay addresses, adapters
translation_templatedefinition, lang, optional prefixoverlay skeleton with the source texts, suggested file name and slots with address, key, placeholders and hash
example_definitionsoptional idList of bundled examples, or one definition
publish_formdefinition, optional form_id, email, success_message, redirect_urlform_id, endpoint, hosted_url, embed_snippet, react_snippet, dashboard_url, warnings
list_formsnoneForms the API key reaches with status, version, submission count and endpoint
get_submissionsform_id, optional limit, cursorsubmissions and next_cursor
update_form_settingsform_id, optional webhook_url, notify_mode, success_message, redirect_url, statusform_id, status, success_message, redirect_url, notify_mode, webhook_url, masked webhook_secret
get_webhookform_idurl and the masked secret
reveal_webhook_secretform_idform_id and the full webhook_secret. Marked as a non-read-only, sensitive tool. Whether the client asks first depends on its permission settings

publish_form, list_forms, get_submissions, update_form_settings, get_webhook and reveal_webhook_secret call Formhaus Cloud at https://api.formhaus.dev. All but publish_form need FORMHAUS_API_KEY in the server environment, and publish_form uses it when set. An account key (fh_live_...) reaches every form and all six tools. An agent key (fh_agent_..., returned once by the first keyless publish_form) reaches only the forms it created, and update_form_settings, get_webhook and reveal_webhook_secret need an account key. The server reads FORMHAUS_API_KEY from its own environment, not from the project .env. Add it to the env of the formhaus server in your MCP client config (for example .mcp.json with ${FORMHAUS_API_KEY} and the value in your shell or a gitignored .env your client loads), then restart the server. FORMHAUS_API_BASE overrides the API URL. The server also sends short usage instructions to the client on connect.

simulate_path applies answers as initial values, with group answers as arrays of item objects, then presses the actions in order, or Next until the last step or the first blocking error. errors covers visited steps only. Custom validators, onStepValidate and lifecycle hooks are not run. The capabilities are also available as the formhaus://capabilities resource.

The tool handlers are exported for use without MCP:

ts
import { simulatePathTool, validateDefinitionTool } from '@formhaus/mcp';
const report = await validateDefinitionTool({ definition });const result = await simulatePathTool({ definition, answers: { kind: 'business' } });

See the MCP guide for example output. A remote MCP server for Formhaus Cloud is also available. npx formhaus sets up the server in the coding agents on your machine; see formhaus.

License

MIT

Source: packages/mcp/README.md at commit cf472c1

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

14
  1. v0.6.3LatestOct 18, 2026
  2. v0.6.2Oct 18, 2026
  3. v0.6.1Oct 16, 2026
  4. v0.5.2Oct 16, 2026
  5. v0.5.0Oct 15, 2026
  6. v0.4.2Oct 15, 2026
  7. v0.4.0Oct 15, 2026
  8. v0.3.4Oct 14, 2026
  9. v0.3.3Oct 14, 2026
  10. v0.3.2Oct 14, 2026
  11. v0.3.1Oct 12, 2026
  12. v0.2.1Oct 11, 2026
  13. v0.2.0Oct 11, 2026
  14. v0.1.2Oct 9, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts