> ## Documentation Index
> Fetch the complete documentation index at: https://retrievalcontextprotocol.com/llms.txt
> Use this file to discover all available pages before exploring further.

# JSON Schema

> The normative JSON Schema (draft 2020-12) for every RCP/1 message shape.

Every RCP/1 message shape — requests, results, errors, capabilities, hits,
filters, Content blocks — is described by a normative
[JSON Schema (draft 2020-12)](https://json-schema.org/) at
[`/schema/rcp-1.0.json`](https://github.com/1ay1/rcp/blob/main/schema/rcp-1.0.json).

<Card title="Download the schema" icon="download" href="https://raw.githubusercontent.com/1ay1/rcp/main/schema/rcp-1.0.json">
  `schema/rcp-1.0.json` — validate messages, generate types, or drive a linter.
</Card>

## Using it

<CardGroup cols={2}>
  <Card title="Validate messages" icon="circle-check">
    Point any draft-2020-12 validator (ajv, `jsonschema`, `jschema`) at a message
    to check conformance in tests and CI.
  </Card>

  <Card title="Generate types" icon="wand-magic-sparkles">
    Feed it to `quicktype`, `datamodel-code-generator`, or
    `json-schema-to-typescript` to derive types in your language.
  </Card>
</CardGroup>

```sh theme={null}
# Validate a captured message with ajv
npx ajv-cli validate -s schema/rcp-1.0.json -d captured-message.json

# Generate TypeScript types
npx json-schema-to-typescript schema/rcp-1.0.json > rcp.d.ts
```

<Note>
  The schema is a companion to the prose specification, not a replacement: where
  the schema constrains **shape**, the [specification](/reference/specification)
  constrains **behaviour** (gating, negotiation, error semantics). A message can be
  schema-valid and still violate a MUST — conformance requires both.
</Note>

<Info>
  The reference [SDKs](/sdks/overview) already encode these shapes, so if you build
  on an SDK you get schema-correct messages for free.
</Info>