2e7108d366## Motivation and Context Docs currently don't have very clear organisation, and don't explain core flows. This fixes #89 (although we still might want to push these to `https://modelcontextprotocol.io/docs/`), based on the plan there. One minor change from that plan is that I merged tutorials and guides, because they ended up basically being duplicates which I thought would be annoying for us to keep in sync. Additionally in the Diátaxis framework, tutorials and guides are separated by whether they are focused on acquisition of skills (e.g. in a learning environment) or application of skills (e.g. in a work environment). I expect the registry to be something that will be used occasionally in a work environment, rather than a fundamental 'learnable' skill so I think it's reasonable not to have tutorials and fold these into guides. ## How Has This Been Tested? - Read through all these updated docs - Unit and integration tests (that previously used examples.md and use the schema) working - Ran `npx markdown-link-check .` to check all the links work ## Breaking Changes Links to old docs will break, but I don't think there are any. All internal links have been checked and updated. ## Types of changes <!-- What types of changes does your code introduce? Put an `x` in all the boxes that apply: --> - [ ] Bug fix (non-breaking change which fixes an issue) - [ ] New feature (non-breaking change which adds functionality) - [ ] Breaking change (fix or feature that would cause existing functionality to change) - [x] Documentation update
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server.json Format Specification
A server.json file is a standardized way to describe MCP servers for registry publishing, client discovery, and package management.
Also see:
- For step-by-step instructions on creating and using server.json files, see the publishing guide.
- For understanding the validation requirements when publishing to the official registry, see official registry requirements.
Browse the Complete Schema
📋 View the full specification interactively: Open server.schema.json in a schema viewer like json-schema.app.
The schema contains all field definitions, validation rules, examples, and detailed descriptions.
The official registry has some more restrictions on top of this. See the official registry requirements for details.
Examples
Basic Server with NPM Package
{
"$schema": "https://static.modelcontextprotocol.io/schemas/2025-07-09/server.schema.json",
"name": "io.modelcontextprotocol/brave-search",
"description": "MCP server for Brave Search API integration",
"status": "active",
"repository": {
"url": "https://github.com/modelcontextprotocol/servers",
"source": "github"
},
"version_detail": {
"version": "1.0.2"
},
"packages": [
{
"registry_type": "npm",
"registry_base_url": "https://registry.npmjs.org",
"identifier": "@modelcontextprotocol/server-brave-search",
"version": "1.0.2",
"transport": {
"type": "stdio"
},
"environment_variables": [
{
"name": "BRAVE_API_KEY",
"description": "Brave Search API Key",
"is_required": true,
"is_secret": true
}
]
}
],
"_meta": {
"publisher": {
"tool": "npm-publisher",
"version": "1.0.1",
"build_info": {
"timestamp": "2023-12-01T10:30:00Z"
}
}
}
}
Server in a Monorepo with Subfolder
For MCP servers located within a subdirectory of a larger repository (monorepo structure), use the subfolder field to specify the relative path:
{
"$schema": "https://static.modelcontextprotocol.io/schemas/2025-07-09/server.schema.json",
"name": "io.modelcontextprotocol/everything",
"description": "MCP server that exercises all the features of the MCP protocol",
"status": "active",
"repository": {
"url": "https://github.com/modelcontextprotocol/servers",
"source": "github",
"subfolder": "src/everything"
},
"version_detail": {
"version": "0.6.2"
},
"packages": [
{
"registry_type": "npm",
"registry_base_url": "https://registry.npmjs.org",
"identifier": "@modelcontextprotocol/everything",
"version": "0.6.2",
"transport": {
"type": "stdio"
}
}
],
"_meta": {
"publisher": {
"tool": "npm-publisher",
"version": "1.0.1",
"build_info": {
"timestamp": "2023-12-01T10:30:00Z"
}
}
}
}
Constant (fixed) arguments needed to start the MCP server
Suppose your MCP server application requires a mcp start CLI arguments to start in MCP server mode. Express these as positional arguments like this:
{
"name": "io.github.joelverhagen/knapcode-samplemcpserver",
"description": "Sample NuGet MCP server for a random number and random weather",
"version_detail": {
"version": "0.4.0-beta"
},
"packages": [
{
"registry_type": "nuget",
"registry_base_url": "https://api.nuget.org",
"identifier": "Knapcode.SampleMcpServer",
"version": "0.4.0-beta",
"transport": {
"type": "stdio"
},
"package_arguments": [
{
"type": "positional",
"value": "mcp"
},
{
"type": "positional",
"value": "start"
}
]
}
],
"_meta": {
"publisher": {
"tool": "nuget-publisher",
"version": "2.1.0",
"build_info": {
"timestamp": "2023-11-15T14:22:00Z",
"pipeline_id": "nuget-build-456"
}
}
}
}
This will essentially instruct the MCP client to execute dnx Knapcode.SampleMcpServer@0.4.0-beta -- mcp start instead of the default dnx Knapcode.SampleMcpServer@0.4.0-beta (when no package_arguments are provided).
Filesystem Server with Multiple Packages
{
"$schema": "https://static.modelcontextprotocol.io/schemas/2025-07-09/server.schema.json",
"name": "io.github.modelcontextprotocol/filesystem",
"description": "Node.js server implementing Model Context Protocol (MCP) for filesystem operations.",
"status": "active",
"repository": {
"url": "https://github.com/modelcontextprotocol/servers",
"source": "github",
"id": "b94b5f7e-c7c6-d760-2c78-a5e9b8a5b8c9"
},
"version_detail": {
"version": "1.0.2"
},
"packages": [
{
"registry_type": "npm",
"registry_base_url": "https://registry.npmjs.org",
"identifier": "@modelcontextprotocol/server-filesystem",
"version": "1.0.2",
"transport": {
"type": "stdio"
},
"package_arguments": [
{
"type": "positional",
"value_hint": "target_dir",
"description": "Path to access",
"default": "/Users/username/Desktop",
"is_required": true,
"is_repeated": true
}
],
"environment_variables": [
{
"name": "LOG_LEVEL",
"description": "Logging level (debug, info, warn, error)",
"default": "info"
}
]
},
{
"registry_type": "oci",
"registry_base_url": "https://docker.io",
"identifier": "mcp/filesystem",
"version": "1.0.2",
"transport": {
"type": "stdio"
},
"runtime_arguments": [
{
"type": "named",
"description": "Mount a volume into the container",
"name": "--mount",
"value": "type=bind,src={source_path},dst={target_path}",
"is_required": true,
"is_repeated": true,
"variables": {
"source_path": {
"description": "Source path on host",
"format": "filepath",
"is_required": true
},
"target_path": {
"description": "Path to mount in the container. It should be rooted in `/project` directory.",
"is_required": true,
"default": "/project"
}
}
}
],
"package_arguments": [
{
"type": "positional",
"value_hint": "target_dir",
"value": "/project"
}
],
"environment_variables": [
{
"name": "LOG_LEVEL",
"description": "Logging level (debug, info, warn, error)",
"default": "info"
}
]
}
],
"_meta": {
"publisher": {
"tool": "ci-publisher",
"version": "3.2.1",
"build_info": {
"commit": "a1b2c3d4e5f6789",
"timestamp": "2023-12-01T10:30:00Z",
"pipeline_id": "filesystem-build-789",
"environment": "production"
}
}
}
}
Remote Server Example
{
"name": "io.modelcontextprotocol.anonymous/mcp-fs",
"description": "Cloud-hosted MCP filesystem server",
"repository": {
"url": "https://github.com/example/remote-fs",
"source": "github",
"id": "xyz789ab-cdef-0123-4567-890ghijklmno"
},
"version_detail": {
"version": "2.0.0"
},
"remotes": [
{
"type": "sse",
"url": "http://mcp-fs.anonymous.modelcontextprotocol.io/sse"
}
],
"_meta": {
"publisher": {
"tool": "cloud-deployer",
"version": "2.4.0",
"build_info": {
"commit": "f7e8d9c2b1a0",
"timestamp": "2023-12-05T08:45:00Z",
"deployment_id": "remote-fs-deploy-456",
"region": "us-west-2"
}
}
}
}
Python Package Example
{
"name": "io.github.example/weather-mcp",
"description": "Python MCP server for weather data access",
"repository": {
"url": "https://github.com/example/weather-mcp",
"source": "github",
"id": "def456gh-ijkl-7890-mnop-qrstuvwxyz12"
},
"version_detail": {
"version": "0.5.0"
},
"packages": [
{
"registry_type": "pypi",
"registry_base_url": "https://pypi.org",
"identifier": "weather-mcp-server",
"version": "0.5.0",
"runtime_hint": "uvx",
"transport": {
"type": "stdio"
},
"environment_variables": [
{
"name": "WEATHER_API_KEY",
"description": "API key for weather service",
"is_required": true,
"is_secret": true
},
{
"name": "WEATHER_UNITS",
"description": "Temperature units (celsius, fahrenheit)",
"default": "celsius"
}
]
}
],
"_meta": {
"publisher": {
"tool": "poetry-publisher",
"version": "1.8.3",
"build_info": {
"python_version": "3.11.5",
"timestamp": "2023-11-28T16:20:00Z",
"build_id": "pypi-weather-123",
"dependencies_hash": "sha256:a9b8c7d6e5f4"
}
}
}
}
NuGet (.NET) Package Example
The dnx tool ships with the .NET 10 SDK, starting with Preview 6.
{
"name": "io.github.joelverhagen/knapcode-samplemcpserver",
"description": "Sample NuGet MCP server for a random number and random weather",
"repository": {
"url": "https://github.com/joelverhagen/Knapcode.SampleMcpServer",
"source": "github",
"id": "example-nuget-id-0000-1111-222222222222"
},
"version_detail": {
"version": "0.5.0"
},
"packages": [
{
"registry_type": "nuget",
"registry_base_url": "https://api.nuget.org",
"identifier": "Knapcode.SampleMcpServer",
"version": "0.5.0",
"runtime_hint": "dnx",
"transport": {
"type": "stdio"
},
"environment_variables": [
{
"name": "WEATHER_CHOICES",
"description": "Comma separated list of weather descriptions to randomly select.",
"is_required": true,
"is_secret": false
}
]
}
],
"_meta": {
"publisher": {
"tool": "dotnet-publisher",
"version": "8.0.100",
"build_info": {
"dotnet_version": "8.0.0",
"timestamp": "2023-12-10T12:15:00Z",
"configuration": "Release",
"target_framework": "net8.0",
"build_number": "20231210.1"
}
}
}
}
Complex Docker Server with Multiple Arguments
{
"name": "io.github.example/database-manager",
"description": "MCP server for database operations with support for multiple database types",
"repository": {
"url": "https://github.com/example/database-manager-mcp",
"source": "github",
"id": "ghi789jk-lmno-1234-pqrs-tuvwxyz56789"
},
"version_detail": {
"version": "3.1.0"
},
"packages": [
{
"registry_type": "oci",
"registry_base_url": "https://docker.io",
"identifier": "example/database-manager-mcp",
"version": "3.1.0",
"transport": {
"type": "stdio"
},
"runtime_arguments": [
{
"type": "named",
"name": "--network",
"value": "host",
"description": "Use host network mode"
},
{
"type": "named",
"name": "-e",
"value": "DB_TYPE={db_type}",
"description": "Database type to connect to",
"is_repeated": true,
"variables": {
"db_type": {
"description": "Type of database",
"choices": [
"postgres",
"mysql",
"mongodb",
"redis"
],
"is_required": true
}
}
}
],
"package_arguments": [
{
"type": "named",
"name": "--host",
"description": "Database host",
"default": "localhost",
"is_required": true
},
{
"type": "named",
"name": "--port",
"description": "Database port",
"format": "number"
},
{
"type": "positional",
"value_hint": "database_name",
"description": "Name of the database to connect to",
"is_required": true
}
],
"environment_variables": [
{
"name": "DB_USERNAME",
"description": "Database username",
"is_required": true
},
{
"name": "DB_PASSWORD",
"description": "Database password",
"is_required": true,
"is_secret": true
},
{
"name": "SSL_MODE",
"description": "SSL connection mode",
"default": "prefer",
"choices": [
"disable",
"prefer",
"require"
]
}
]
}
],
"_meta": {
"publisher": {
"tool": "docker-buildx",
"version": "0.12.1",
"build_info": {
"docker_version": "24.0.7",
"timestamp": "2023-12-08T14:30:00Z",
"platform": "linux/amd64,linux/arm64",
"registry": "docker.io",
"image_digest": "sha256:1a2b3c4d5e6f7890"
}
}
}
}
Server with Remote and Package Options
{
"$schema": "https://static.modelcontextprotocol.io/schemas/2025-07-09/server.schema.json",
"name": "io.modelcontextprotocol.anonymous/hybrid-mcp",
"description": "MCP server available as both local package and remote service",
"repository": {
"url": "https://github.com/example/hybrid-mcp",
"source": "github",
"id": "klm012no-pqrs-3456-tuvw-xyz789abcdef"
},
"version_detail": {
"version": "1.5.0"
},
"packages": [
{
"registry_type": "npm",
"registry_base_url": "https://registry.npmjs.org",
"identifier": "@example/hybrid-mcp-server",
"version": "1.5.0",
"runtime_hint": "npx",
"transport": {
"type": "stdio"
},
"package_arguments": [
{
"type": "named",
"name": "--mode",
"description": "Operation mode",
"default": "local",
"choices": [
"local",
"cached",
"proxy"
]
}
]
}
],
"remotes": [
{
"type": "sse",
"url": "https://mcp.anonymous.modelcontextprotocol.io/sse",
"headers": [
{
"name": "X-API-Key",
"description": "API key for authentication",
"is_required": true,
"is_secret": true
},
{
"name": "X-Region",
"description": "Service region",
"default": "us-east-1",
"choices": [
"us-east-1",
"eu-west-1",
"ap-southeast-1"
]
}
]
},
{
"type": "streamable-http",
"url": "https://mcp.anonymous.modelcontextprotocol.io/http"
}
],
"_meta": {
"publisher": {
"tool": "hybrid-deployer",
"version": "1.7.2",
"build_info": {
"timestamp": "2023-12-03T11:00:00Z",
"deployment_strategy": "blue-green",
"npm_version": "10.2.4",
"node_version": "20.10.0",
"service_endpoints": {
"sse": "deployed",
"streamable": "deployed"
}
}
}
}
}
MCP Bundle (MCPB) Package Example
{
"name": "io.modelcontextprotocol/text-editor",
"description": "MCP Bundle server for advanced text editing capabilities",
"repository": {
"url": "https://github.com/modelcontextprotocol/text-editor-mcpb",
"source": "github"
},
"version_detail": {
"version": "1.0.2"
},
"packages": [
{
"registry_type": "mcpb",
"registry_base_url": "https://github.com",
"identifier": "https://github.com/modelcontextprotocol/text-editor-mcpb/releases/download/v1.0.2/text-editor.mcpb",
"version": "1.0.2",
"file_sha256": "fe333e598595000ae021bd27117db32ec69af6987f507ba7a63c90638ff633ce",
"transport": {
"type": "stdio"
}
}
],
"_meta": {
"publisher": {
"tool": "mcpb-publisher",
"version": "1.0.0",
"build_info": {
"timestamp": "2023-12-02T09:15:00Z",
"bundle_format": "mcpb-v1"
}
}
}
}
This example shows an MCPB (MCP Bundle) package that:
- Is hosted on GitHub Releases (an allowlisted provider)
- Includes a SHA-256 hash for integrity verification
- Can be downloaded and executed directly by MCP clients that support MCPB
Embedded MCP inside a CLI tool
Some CLI tools bundle an MCP server, without a standalone MCP package or a public repository. In these cases, reuse the existing packages shape by pointing at the host CLI package and supplying the package_arguments and runtime_hint if needed to start the MCP server.
{
"$schema": "https://static.modelcontextprotocol.io/schemas/2025-07-09/server.schema.json",
"name": "io.snyk/cli-mcp",
"description": "MCP server provided by the Snyk CLI",
"status": "active",
"version_detail": {
"version": "1.1298.0"
},
"packages": [
{
"registry_type": "npm",
"registry_base_url": "https://registry.npmjs.org",
"identifier": "snyk",
"version": "1.1298.0",
"transport": {
"type": "stdio"
},
"package_arguments": [
{ "type": "positional", "value": "mcp" },
{
"type": "named",
"name": "-t",
"description": "Transport type for MCP server",
"default": "stdio",
"choices": ["stdio", "sse"]
}
]
}
]
}
Deprecated Server Example
{
"name": "io.github.example/old-weather",
"description": "Legacy weather server - DEPRECATED: Use weather-v2 instead for new projects",
"status": "deprecated",
"repository": {
"url": "https://github.com/example/old-weather",
"source": "github",
"id": "legacy-abc123-def456-789012-345678-901234567890"
},
"version_detail": {
"version": "0.9.5"
},
"packages": [
{
"registry_type": "npm",
"registry_base_url": "https://registry.npmjs.org",
"identifier": "@legacy/old-weather-server",
"version": "0.9.5",
"transport": {
"type": "stdio"
},
"environment_variables": [
{
"name": "WEATHER_API_KEY",
"description": "Weather API key",
"is_required": true,
"is_secret": true
}
]
}
],
"_meta": {
"publisher": {
"tool": "legacy-publisher",
"version": "0.8.1",
"build_info": {
"timestamp": "2023-06-15T09:30:00Z",
"deprecation_notice": "This publisher is deprecated. Use npm-publisher v2.0+ for new projects.",
"maintenance_mode": true,
"final_version": true
}
}
}
}