Model Context Protocol

https://modelcontextprotocol.io/specification/2026-07-28
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Model Context Protocol (MCP) is an open, standardized protocol that enables seamless, secure...
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### Project directory root example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example of a project directory root with a file:// URI and an optional name.

```json
{  
  "uri": "file:///home/user/projects/myproject",  
  "name": "My Project"  
}
```

--------------------------------

### Example Discover request

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example JSON-RPC request for server/discover. Includes protocol version, client info, and client capabilities in the _meta field.

```json
{  
  “jsonrpc”: “2.0”,  
  “id”: “discover-1”,  
  “method”: “server/discover”,  
  “params”: {  
    “_meta”: {  
      “io.modelcontextprotocol/protocolVersion”: “2026-07-28”,  
      “io.modelcontextprotocol/clientInfo”: {  
        “name”: “ExampleClient”,  
        “version”: “1.0.0”  
      },  
      “io.modelcontextprotocol/clientCapabilities”: {}  
    }  
  }  
}
```

--------------------------------

### Multiple root directories example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example response with multiple root directories, each with a file:// URI and an optional name.

```json
{  
  "roots": [  
    {  
      "uri": "file:///home/user/repos/frontend",  
      "name": "Frontend Repository"  
    },  
    {  
      "uri": "file:///home/user/repos/backend",  
      "name": "Backend Repository"  
    }  
  ]  
}
```

--------------------------------

### List resources request example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example request for listing resources. Includes protocol version, client info, and capabilities in the metadata.

```json
{  
  “jsonrpc”: “2.0”,  
  “id”: “list-resources-example”,  
  “method”: “resources/list”,  
  “params”: {  
    “_meta”: {  
      “io.modelcontextprotocol/protocolVersion”: “2026-07-28”,  
      “io.modelcontextprotocol/clientInfo”: {  
        “name”: “ExampleClient”,  
        “version”: “1.0.0”  
      },  
      “io.modelcontextprotocol/clientCapabilities”: {}  
    }  
  }  
}
```

--------------------------------

### Example prompts/list request

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example JSON-RPC request for listing prompts. Includes protocol version, client info, and capabilities in the _meta field.

```json
{  
  “jsonrpc”: “2.0”,  
  “id”: “list-prompts-example”,  
  “method”: “prompts/list”,  
  “params”: {  
    “_meta”: {  
      “io.modelcontextprotocol/protocolVersion”: “2026-07-28”,  
      “io.modelcontextprotocol/clientInfo”: {  
        “name”: “ExampleClient”,  
        “version”: “1.0.0”  
      },  
      “io.modelcontextprotocol/clientCapabilities”: {}  
    }  
  }  
}
```

--------------------------------

### Single root directory example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example response with a single root directory. The root has a file:// URI and an optional name.

```json
{  
  "roots": [  
    {  
      "uri": "file:///home/user/projects/myproject",  
      "name": "My Project"  
    }  
  ]  
}
```

--------------------------------

### Resource with Annotations Example

Source: https://modelcontextprotocol.io/specification/2026-07-28/server/resources

Example resource with annotations. The `annotations` object includes `audience`, `priority`, and `lastModified` fields.

```json
{
  "uri": "file:///project/README.md",
  "name": "README.md",
  "title": "Project Documentation",
  "mimeType": "text/markdown",
  "annotations": {
    "audience": ["user"],
    "priority": 0.8,
    "lastModified": "2025-01-12T15:00:58Z"
  }
}
```

--------------------------------

### Binary Content Resource Example

Source: https://modelcontextprotocol.io/specification/2026-07-28/server/resources

Example of a resource with binary content. The `blob` field holds base64-encoded data.

```json
{
  "uri": "file:///example.png",
  "mimeType": "image/png",
  "blob": "base64-encoded-data"
}
```

--------------------------------

### Text Content Resource Example

Source: https://modelcontextprotocol.io/specification/2026-07-28/server/resources

Example of a resource with text content. The `text` field holds the resource data.

```json
{
  "uri": "file:///example.txt",
  "mimeType": "text/plain",
  "text": "Resource content"
}
```

--------------------------------

### Tool call params with progress token example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example params object for a build_simulation tool call that includes a progressToken in _meta for progress tracking.

```json
{  
  “_meta”: {  
    “io.modelcontextprotocol/protocolVersion”: “2026-07-28”,  
    “io.modelcontextprotocol/clientInfo”: {  
      “name”: “ExampleClient”,  
      “version”: “1.0.0”  
    },  
    “io.modelcontextprotocol/clientCapabilities”: {},  
    “progressToken”: “oivaizmir”  
  },  
  “name”: “build_simulation”,  
  “arguments”: {  
    “city”: “Micropolis”  
  }  
}
```

--------------------------------

### List roots request example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example JSON-RPC request for listing roots. The method is "roots/list" and the id is "list-roots-example".

```json
{  
  "id": "list-roots-example",  
  "method": "roots/list"  
}
```

--------------------------------

### Single completion value example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example result with a single completion value “flask”. total is 1 and hasMore is false.

```json
{  
  “resultType”: “complete”,  
  “completion”: {  
    “values”: [“flask”],  
    “total”: 1,  
    “hasMore”: false  
  }  
}
```

--------------------------------

### Example Discover result response

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example JSON-RPC response for a server/discover request. Shows a complete result with supported versions, capabilities, server info, TTL, and cache scope.

```json
{  
  “jsonrpc”: “2.0”,  
  “id”: “discover-1”,  
  “result”: {  
    “resultType”: “complete”,  
    “supportedVersions”: [“2026-07-28”],  
    “capabilities”: {  
      “tools”: {},  
      “resources”: {}  
    },  
    “_meta”: {  
      “io.modelcontextprotocol/serverInfo”: {  
        “name”: “ExampleServer”,  
        “version”: “1.0.0”  
      }  
    },  
    “ttlMs”: 3600000,  
    “cacheScope”: “public”  
  }  
}
```

--------------------------------

### get_weather tool call params example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example params object for a get_weather tool call, showing the required _meta and name fields with an arguments map.

```json
{  
  “_meta”: {  
    “io.modelcontextprotocol/protocolVersion”: “2026-07-28”,  
    “io.modelcontextprotocol/clientInfo”: {  
      “name”: “ExampleClient”,  
      “version”: “1.0.0”  
    },  
    “io.modelcontextprotocol/clientCapabilities”: {}  
  },  
  “name”: “get_weather”,  
  “arguments”: {  
    “location”: “New York”  
  }  
}
```

--------------------------------

### Multiple completion values with more available example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example result with multiple completion values and more available. values contains three items, total is 10, and hasMore is true.

```json
{  
  “resultType”: “complete”,  
  “completion”: {  
    “values”: [“python”, “pytorch”, “pyside”],  
    “total”: 10,  
    “hasMore”: true  
  }  
}
```

--------------------------------

### Example Request with Bearer Token

Source: https://modelcontextprotocol.io/specification/2026-07-28/basic/authorization

Example HTTP request showing the Authorization header with a bearer token. The token is an example JWT.

```http
GET /mcp HTTP/1.1
Host: mcp.example.com
Authorization: Bearer eyJhbGciOiJIUzI1NiIs...

```

--------------------------------

### Explicit dialect (draft-07) JSON Schema example

Source: https://modelcontextprotocol.io/specification/2026-07-28/basic

Example of a JSON Schema with an explicit $schema field specifying draft-07. This schema defines the same object structure as the default dialect example but explicitly declares the dialect.

```json
{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "name": { "type": "string" },
    "age": { "type": "integer", "minimum": 0 }
  },
  "required": ["name"]
}
```

--------------------------------

### SamplingMessage example: single content block

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example of a SamplingMessage with a single text content block.

```json
{  
  “role”: “user”,  
  “content”: {  
    “type”: “text”,  
    “text”: “What is the capital of France?”  
  }  
}
```

--------------------------------

### SamplingMessage example: multiple content blocks

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example of a SamplingMessage with multiple content blocks, each containing a tool result.

```json
{  
  “role”: “user”,  
  “content”: [  
    {  
      “type”: “tool_result”,  
      “toolUseId”: “call_123”,  
      “content”: [{ “type”: “text”, “text”: “Result 1” }]  
    },  
    {  
      “type”: “tool_result”,  
      “toolUseId”: “call_456”,  
      “content”: [{ “type”: “text”, “text”: “Result 2” }]  
    }  
  ]  
}
```

--------------------------------

### Model Preferences Example

Source: https://modelcontextprotocol.io/specification/2026-07-28/client/sampling

Shows how a server expresses model preferences using hints and capability priorities. Hints are substrings evaluated in order, and clients may map them to equivalent models from other providers.

```json
{
  "hints": [
    { "name": "claude-3-sonnet" }, // Prefer Sonnet-class models
    { "name": "claude" } // Fall back to any Claude model
  ],
  "costPriority": 0.3, // Cost is less important
  "speedPriority": 0.8, // Speed is very important
  "intelligencePriority": 0.5 // Moderate capability needs
}
```

--------------------------------

### Root object for a project directory

Source: https://modelcontextprotocol.io/specification/2026-07-28/client

Example root object for a project directory. The uri must be a file:// URI.

```json
{
  "uri": "file:///home/user/projects/myproject",
  "name": "My Project"
}
```

--------------------------------

### List resource templates request example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example JSON-RPC request to list resource templates. It includes the protocol version, client info, and empty client capabilities in the _meta object.

```json
{  
  “jsonrpc”: “2.0”,  
  “id”: “list-resource-templates-example”,  
  “method”: “resources/templates/list”,  
  “params”: {  
    “_meta”: {  
      “io.modelcontextprotocol/protocolVersion”: “2026-07-28”,  
      “io.modelcontextprotocol/clientInfo”: {  
        “name”: “ExampleClient”,  
        “version”: “1.0.0”  
      },  
      “io.modelcontextprotocol/clientCapabilities”: {}  
    }  
  }  
}
```

--------------------------------

### subscriptions/listen request example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example request for the subscriptions/listen method. The client opens a long-lived channel and opts in to toolsListChanged and resourceSubscriptions notifications. The server MUST NOT send notification types not explicitly requested.

```json
{
  "jsonrpc": "2.0",
  "id": "listen-1",
  "method": "subscriptions/listen",
  "params": {
    "_meta": {
      "io.modelcontextprotocol/protocolVersion": "2026-07-28",
      "io.modelcontextprotocol/clientInfo": {
        "name": "ExampleClient",
        "version": "1.0.0"
      },
      "io.modelcontextprotocol/clientCapabilities": {}
    },
    "notifications": {
      "toolsListChanged": true,
      "resourceSubscriptions": ["file:///project/config.json"]
    }
  }
}
```

--------------------------------

### OpenTelemetry trace context in _meta (JSON-RPC example)

Source: https://modelcontextprotocol.io/specification/2026-07-28/basic

Non-normative example showing trace context propagation in a JSON-RPC request's _meta field. The example includes a tools/call request with a traceparent value following W3C Trace Context format.

```json
{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "get_weather",
    "arguments": {
      "location": "New York"
    },
    "_meta": {
      "traceparent": "00-0af7651916cd43dd8448eb211c80319c-00f067aa0ba902b7-01"
    }
  }
}
```

--------------------------------

### Resource templates list with cursor and TTL example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example result object for a resources/templates/list response. Includes a nextCursor for pagination, a TTL of 3600000 ms, and a public cache scope.

```json
{  
  “resultType”: “complete”,  
  “resourceTemplates”: [  
    {  
      “uriTemplate”: “file:///{path}”,  
      “name”: “Project Files”,  
      “title”: ”📁 Project Files”,  
      “description”: “Access files in the project directory”,  
      “mimeType”: “application/octet-stream”,  
      “icons”: [  
        {  
          “src”: “https://example.com/folder-icon.png”,  
          “mimeType”: “image/png”,  
          “sizes”: [“48x48”]  
        }  
      ]  
    }  
  ],  
  “nextCursor”: “next-page-cursor”,  
  “ttlMs”: 3600000,  
  “cacheScope”: “public”  
}
```

--------------------------------

### File resource with annotations

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example of a file resource with annotations. Shows how to set the `uri`, `name`, `title`, `mimeType`, and `annotations` fields.

```json
{  
  “uri”: “file:///project/README.md”,  
  “name”: “README.md”,  
  “title”: “Project Documentation”,  
  “mimeType”: “text/markdown”,  
  “annotations”: {  
    “audience”: [“user”],  
    “priority”: 0.8,  
    “lastModified”: “2025-01-12T15:00:58Z”  
  }  
}
```

--------------------------------

### Roots array for multiple repositories

Source: https://modelcontextprotocol.io/specification/2026-07-28/client

Example roots array for multiple repositories.

```json
[
  {
    "uri": "file:///home/user/repos/frontend",
    "name": "Frontend Repository"
  },
  {
    "uri": "file:///home/user/repos/backend",
    "name": "Backend Repository"
  }
]
```

--------------------------------

### List resource templates result response example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example JSON response for a resources/templates/list request. Shows a complete result with a single resource template, a TTL of 3600000 ms, and a public cache scope.

```json
{  
  “jsonrpc”: “2.0”,  
  “id”: “list-resource-templates-example”,  
  “result”: {  
    “resultType”: “complete”,  
    “resourceTemplates”: [  
      {  
        “uriTemplate”: “file:///{path}”,  
        “name”: “Project Files”,  
        “title”: “Project Files”,  
        “description”: “Access files in the project directory”,  
        “mimeType”: “application/octet-stream”,  
        “icons”: [  
          {  
            “src”: “https://example.com/folder-icon.png”,  
            “mimeType”: “image/png”,  
            “sizes”: [“48x48”]  
          }  
        ]  
      }  
    ],  
    “ttlMs”: 3600000,  
    “cacheScope”: “public”  
  }  
}
```

--------------------------------

### ResourceUpdatedNotificationParams interface and example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Defines the ResourceUpdatedNotificationParams interface and shows an example params object. The uri may be a sub-resource of the one the client subscribed to.

```typescript
interface ResourceUpdatedNotificationParams {  
_meta?: NotificationMetaObject;  
uri: string;  
}
```

```json
{  
  "uri": "file:///project/src/main.rs"  
}
```

--------------------------------

### Example: Log database connection failed (notifications/message)

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example notification for a failed database connection. Deprecated as of protocol version 2026-07-28 (SEP-2577).

```json
{  
  “jsonrpc”: “2.0”,  
  “method”: “notifications/message”,  
  “params”: {  
    “level”: “error”,  
    “logger”: “database”,  
    “data”: {  
      “error”: “Connection failed”,  
      “details”: {  
        “host”: “localhost”,  
        “port”: 5432  
      }  
    }  
  }  
}
```

--------------------------------

### CancelledNotificationParams example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example of the params object for a notifications/cancelled notification. The requestId is required and must correspond to a previously issued request; reason is optional.

```json
{
  "requestId": "123",
  "reason": "User requested cancellation"
}
```

--------------------------------

### Client ID Metadata Document Example

Source: https://modelcontextprotocol.io/specification/2026-07-28/basic/authorization/client-registration

Example metadata document that must be hosted at an HTTPS URL and include at least client_id, client_name, and redirect_uris. The client_id value must match the document URL exactly.

```json
{
  "client_id": "https://app.example.com/oauth/client-metadata.json",
  "client_name": "Example MCP Client",
  "client_uri": "https://app.example.com",
  "logo_uri": "https://app.example.com/logo.png",
  "redirect_uris": [
    "http://127.0.0.1:3000/callback",
    "http://localhost:3000/callback"
  ],
  "grant_types": ["authorization_code"],
  "response_types": ["code"],
  "token_endpoint_auth_method": "none"
}
```

--------------------------------

### Sampling request example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Shows a complete sampling request with method, params, messages, model preferences, system prompt, and max tokens. This is the full request structure sent from the server to the client.

```json
{  
  "method": "sampling/createMessage",  
  "params": {  
    "messages": [  
      {  
        "role": "user",  
        "content": {  
          "type": "text",  
          "text": "What is the capital of France?"  
        }  
      }  
    ],  
    "modelPreferences": {  
      "hints": [  
        {  
          "name": "claude-3-sonnet"  
        }  
      ],  
      "intelligencePriority": 0.8,  
      "speedPriority": 0.5  
    },  
    "systemPrompt": "You are a helpful assistant.",  
    "maxTokens": 100  
  }  
}
```

--------------------------------

### Prompt argument completion with context example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example params object for a prompt argument completion with context. It includes previously-resolved variables (language: python) to help complete the “framework” argument.

```json
{  
  “_meta”: {  
    “io.modelcontextprotocol/protocolVersion”: “2026-07-28”,  
    “io.modelcontextprotocol/clientInfo”: {  
      “name”: “ExampleClient”,  
      “version”: “1.0.0”  
    },  
    “io.modelcontextprotocol/clientCapabilities”: {}  
  },  
  “ref”: {  
    “type”: “ref/prompt”,  
    “name”: “code_review”  
  },  
  “argument”: {  
    “name”: “framework”,  
    “value”: “fla”  
  },  
  “context”: {  
    “arguments”: {  
      “language”: “python”  
    }  
  }  
}
```

--------------------------------

### InputRequests example with elicitation and sampling requests

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example of an InputRequests map with two server-initiated requests: an elicitation/create form request for a GitHub username and a sampling/createMessage request asking for the capital of France. Keys are server-assigned identifiers; values are the request objects.

```json
{  
  “github_login”: {  
    “method”: “elicitation/create”,  
    “params”: {  
      “mode”: “form”,  
      “message”: “Please provide your GitHub username”,  
      “requestedSchema”: {  
        “type”: “object”,  
        “properties”: {  
          “name”: {  
            “type”: “string”  
          }  
        },  
        “required”: [“name”]  
      }  
    }  
  },  
  “capital_of_france”: {  
    “method”: “sampling/createMessage”,  
    “params”: {  
      “messages”: [  
        {  
          “role”: “user”,  
          “content”: {  
            “type”: “text”,  
            “text”: “What is the capital of France?”  
          }  
        }  
      ],  
      “maxTokens”: 100  
    }  
  }  
}
```

--------------------------------

### Progress message params example

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example of the params object for a progress notification. It includes the progressToken, progress, total, and message fields as defined in ProgressNotificationParams.

```json
{  
  “progressToken”: “oivaizmir”,  
  “progress”: 50,  
  “total”: 100,  
  “message”: “Reticulating splines…”  
}
```

--------------------------------

### Read resource request

Source: https://modelcontextprotocol.io/specification/2026-07-28/schema

Example of a `resources/read` request. The `params` include `_meta` with protocol version and client info, and the `uri` of the resource to read.

```json
{  
  “jsonrpc”: “2.0”,  
  “id”: “read-resource-example”,  
  “method”: “resources/read”,  
  “params”: {  
    “_meta”: {  
      “io.modelcontextprotocol/protocolVersion”: “2026-07-28”,  
      “io.modelcontextprotocol/clientInfo”: {  
        “name”: “ExampleClient”,  
        “version”: “1.0.0”  
      },  
      “io.modelcontextprotocol/clientCapabilities”: {}  
    },  
    “uri”: “file:///project/src/main.rs”  
  }  
}
```
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