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MCPJungle can proxy any MCP server that speaks the Streamable HTTP transport. Once registered, all tools that server provides are available to every MCP client connected to MCPJungle through the gateway’s /mcp endpoint.

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Register a server with CLI flags

The quickest way to register a Streamable HTTP server is with the register command and inline flags: 
mcpjungle register --name calculator --description "Provides some basic math tools" --url http://127.0.0.1:8000/mcp
MCPJungle connects to the server, loads its tool list, and makes those tools available immediately.
If MCPJungle is running inside Docker on macOS or Windows, the container cannot reach 127.0.0.1 on your host. Use host.docker.internal instead:
mcpjungle register --name calculator --description "Provides some basic math tools" --url http://host.docker.internal:8000/mcp

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Register a server from a config file

For servers that need authentication or custom headers — or when you want to keep registration configs in version control — use a JSON config file: 
mcpjungle register -c ./calculator.json
The full config file format for a Streamable HTTP server: 
{
  "name": "calculator",
  "transport": "streamable_http",
  "description": "Provides some basic math tools",
  "url": "http://127.0.0.1:8000/mcp",
  "bearer_token": "<optional bearer token>",
  "headers": {
    "<custom-header>": "<value>"
  }
}
FieldRequiredDescription
nameYesUnique identifier for this server. No spaces, special characters, or consecutive underscores.
transportYesMust be "streamable_http" for HTTP-based servers.
descriptionNoHuman-readable description surfaced in the CLI and API.
urlYesThe full URL of the MCP server’s endpoint (e.g., https://example.com/mcp).
bearer_tokenNoIf set, MCPJungle adds Authorization: Bearer <token> to every request to this server.
headersNoMap of additional HTTP headers to forward. If Authorization is set here, it overrides bearer_token.

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Authenticating with a bearer token

Many SaaS MCP servers (HuggingFace, Stripe, etc.) require an API token. Pass it with the --bearer-token flag: 
mcpjungle register \
  --name huggingface \
  --description "HuggingFace MCP Server" \
  --url https://huggingface.co/mcp \
  --bearer-token <your-hf-api-token>
Or include it in the config file: 
{
  "name": "huggingface",
  "transport": "streamable_http",
  "description": "HuggingFace MCP Server",
  "url": "https://huggingface.co/mcp",
  "bearer_token": "<your-hf-api-token>"
}
For servers that need a custom Authorization format or additional headers, use the headers field directly: 
{
  "name": "sourcegraph",
  "transport": "streamable_http",
  "url": "https://sourcegraph.mycompany.com/.api/mcp",
  "headers": {
    "Authorization": "token <your-sourcegraph-token>",
    "X-Custom-Header": "custom-value"
  }
}

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Environment variable substitution

Config files support ${VAR_NAME} placeholders in any string field. The CLI resolves them from the environment before sending the request to MCPJungle: 
{
  "name": "affine-main",
  "transport": "streamable_http",
  "description": "AFFiNE workspace MCP server",
  "url": "https://app.affine.pro/api/workspaces/${AFFINE_WORKSPACE_ID}/mcp",
  "bearer_token": "${AFFINE_API_TOKEN}",
  "headers": {
    "X-Workspace": "${AFFINE_WORKSPACE_ID}"
  }
}
If a referenced environment variable is not set when you run mcpjungle register, the command fails with an error. Placeholders must resolve to a value at registration time.
Key rules for substitution:
  • Only the ${VAR_NAME} syntax is recognized — not $VAR_NAME.
  • Placeholders can appear anywhere inside a string value, including as a substring: "prefix-${VAR}-suffix".
  • Substitution runs in the CLI process, so the variable must be set in the shell where you run the command.
  • Nested objects and string arrays are also resolved.

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Tool naming convention

MCPJungle uses a canonical name for every tool that follows the pattern <server-name>__<tool-name> (two underscores): 
github__git_commit
calculator__multiply
context7__get-library-docs
Use this canonical name when calling mcpjungle invoke, mcpjungle usage, or when your MCP client refers to a specific tool.

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Deregister a server

To remove a server from MCPJungle: 
mcpjungle deregister calculator
Deregistering removes the server and all the tools, prompts, and resources it provided. They are no longer visible to MCP clients.

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Configure a custom registry URL

By default, the CLI connects to MCPJungle at http://127.0.0.1:8080. If your server runs on a different host or port, configure the registry URL in one of two ways:
Pass the URL inline with every command:
mcpjungle --registry http://my-server:9000 register --name calculator --url http://127.0.0.1:8000/mcp