MCP servers

The Model Context Protocol (MCP) lets AI assistants and coding agents use tools. JSONPad has an MCP server for its documentation: with it, an agent can search and read these docs, look up the exact contract of any API endpoint, SDK method, command or error code, and check the write rules, flows and schema documents it writes for you before you save them.

The docs server is free, needs no account or token, and can't see or change your data. An MCP server for the API itself, for working with your lists and items, is on its way.

Adding the docs server

The docs server is hosted at https://mcp.jsonpad.io/docs (Streamable HTTP). Add it to your agent with that URL. In Claude Desktop and on claude.ai, go to Settings, then Connectors, and add a custom connector with the URL. In other clients:

1claude mcp add --transport http jsonpad-docs https://mcp.jsonpad.io/docs

The hosted server is always up to date: it's deployed with these docs, so it describes exactly what's live.

Running it locally

The same server is also the @basementuniverse/jsonpad-docs-mcp npm package, which runs on your own machine over stdio. It needs Node.js 22.12 or later.

1claude mcp add jsonpad-docs -- npx -y @basementuniverse/jsonpad-docs-mcp

A local copy carries a snapshot of the docs from when it was published. When JSONPad upgrades the engines that run write rules and flows, it adds a warning to its checks until you update it.

What it can do

Reading the docs:

search_docs searches these docs, the SDK references and the command line tool reference. Exact identifiers work well: error names, headers, SDK methods, commands and variables.
read_doc reads a page, or one section of it, as markdown, and list_docs lists the pages.
list_api_endpoints and get_api_endpoint give an endpoint's full contract: parameters, headers, request body, responses, and the SDK method that calls it.
get_sdk_method and get_cli_command give a method's signature and example, or a command's options.
lookup_error explains an error code, and get_plan_limits gives each plan's limits.

Checking your work:

check_write_rules compiles write rules and runs their tests.
eval_write_rule tries one write against some rules, and shows what every rule evaluated to.
check_flow compiles a flow and runs its tests against in-memory data.
validate_sync_document checks a schema sync document, and every rule set and flow in it.
validate_token_permissions checks token permissions, and warns about rules that probably don't do what you meant.

It also has prompts for common jobs (getting started, designing a schema document, writing rules or a flow, explaining an error, planning token permissions, recovering lost data), and resources for every page and JSON schema.

Checking rules and flows

The checkers use the same engines as the API, at the same versions, so rules and flows that pass here behave the same way when you save them. They run on what you send and nothing else: rule lookups and flow reads find the items in the test document, never your data, and checking doesn't count against your request allowance.

You don't need to call them yourself. Ask your agent for what you want, and it can write, check and fix until the tests pass:

12345678

Write rules for my "moves" list so that only a game's players can add a move,
and only on their turn. Add tests, and check them with the JSONPad docs server
until they pass.

Check jsonpad-schema.json and the rules and flow files it references.

Why would this write be refused? Rules: rules/games.rules. The write: an update
by identity "bob" that changes /turn from "alice" to "bob".

A schema document that references files (rulesFile, flowFile and their tests) can only be checked if the agent sends their contents too, which it can do when it has your files open.

Limits and privacy

The hosted server allows about 120 requests a minute from each IP address, and 30 checks. A check can take up to 10 seconds, and its input can be up to 512 KB. The npm package has no limits of its own.

We log which tools are used and what's searched for, so we can tell where the docs fall short. The logs don't include your IP address, or anything you send to the checkers. See the privacy policy.