MCP Commands¶

Commands for managing external MCP (Model Context Protocol) server connections. MCP allows Lango to connect to external tool servers, automatically discover their tools, and expose them to the agent.

MCP must be enabled in configuration (mcp.enabled = true).

lango mcp <subcommand>

lango mcp list¶

List all configured MCP servers with their type, enabled status, and endpoint.

lango mcp list

Output columns:

Column	Description
NAME	Server name
TYPE	Transport type (`stdio`, `http`, `sse`)
ENABLED	`yes` or `no`
ENDPOINT	Command (stdio) or URL (http/sse)

Example:

$ lango mcp list
NAME            TYPE    ENABLED  ENDPOINT
filesystem      stdio   yes      npx @modelcontextprotocol/server-filesystem
github          http    yes      https://mcp.github.com/v1
slack           sse     yes      https://mcp-slack.example.com/sse

lango mcp add¶

Add a new MCP server configuration.

lango mcp add <name> [flags]

Argument	Required	Description
`name`	Yes	Server name (unique identifier)

Flag	Type	Default	Description
`--type`	string	`stdio`	Transport type: `stdio`, `http`, `sse`
`--command`	string		Executable command (required for `stdio`)
`--args`	string		Comma-separated arguments for the command (`stdio`)
`--url`	string		Endpoint URL (required for `http`/`sse`)
`--env`	strings		Environment variables in `KEY=VALUE` format (repeatable)
`--header`	strings		HTTP headers in `KEY=VALUE` format (repeatable)
`--scope`	string	`user`	Config scope: `user` or `project`
`--safety`	string	`dangerous`	Safety level: `safe`, `moderate`, `dangerous`

Transport Requirements

stdio requires --command (the executable to spawn)
http and sse require --url (the server endpoint)

Examples:

# Add a stdio-based MCP server
$ lango mcp add filesystem \
    --type stdio \
    --command "npx" \
    --args "@modelcontextprotocol/server-filesystem,/home/user/docs" \
    --scope project
MCP server "filesystem" added (scope: project)

# Add an HTTP-based MCP server with authentication
$ lango mcp add github \
    --type http \
    --url "https://mcp.github.com/v1" \
    --header "Authorization=Bearer ghp_xxxx" \
    --safety moderate
MCP server "github" added (scope: user)

# Add an SSE-based MCP server with environment variables
$ lango mcp add slack \
    --type sse \
    --url "https://mcp-slack.example.com/sse" \
    --env "SLACK_TOKEN=xoxb-xxxx"
MCP server "slack" added (scope: user)

lango mcp remove¶

Remove an MCP server configuration. Aliases: rm.

lango mcp remove <name> [--scope <scope>]

Argument	Required	Description
`name`	Yes	Server name to remove

Flag	Type	Default	Description
`--scope`	string		Scope to remove from: `user` or `project` (default: search all scopes)

Example:

$ lango mcp remove filesystem
MCP server "filesystem" removed.

$ lango mcp remove github --scope user
MCP server "github" removed from user scope.

lango mcp get¶

Show detailed information about an MCP server, including its configuration and discovered tools.

lango mcp get <name>

Argument	Required	Description
`name`	Yes	Server name

Example:

$ lango mcp get filesystem
Name:       filesystem
Type:       stdio
Enabled:    yes
Safety:     dangerous
Command:    npx
Args:       @modelcontextprotocol/server-filesystem /home/user/docs
Env vars:   0

Tools (3):
  read_file          Read contents of a file
  write_file         Write contents to a file
  list_directory     List files in a directory

lango mcp test¶

Test connectivity to an MCP server. Performs a handshake, measures latency, counts available tools, and pings the session.

lango mcp test <name>

Argument	Required	Description
`name`	Yes	Server name to test

Example:

$ lango mcp test filesystem
Testing MCP server "filesystem"...
  Transport:  stdio (npx)
  Handshake:  OK (142ms)
  Tools:      3 available
  Ping:       OK

lango mcp enable¶

Enable a previously disabled MCP server.

lango mcp enable <name> [--scope <scope>]

Argument	Required	Description
`name`	Yes	Server name to enable

Flag	Type	Default	Description
`--scope`	string		Scope: `user` or `project` (default: search all scopes)

Example:

$ lango mcp enable github
MCP server "github" enabled.

lango mcp disable¶

Disable an MCP server without removing its configuration.

lango mcp disable <name> [--scope <scope>]

Argument	Required	Description
`name`	Yes	Server name to disable

Flag	Type	Default	Description
`--scope`	string		Scope: `user` or `project` (default: search all scopes)

Example:

$ lango mcp disable slack
MCP server "slack" disabled.

Configuration¶

MCP server configurations are stored in JSON files and merged in priority order:

Scope	File	Description
Profile	Active config profile	Base MCP settings (`mcp.enabled`, `mcp.defaultTimeout`)
User	`~/.lango/mcp.json`	User-wide server definitions
Project	`.lango-mcp.json`	Project-specific server definitions (highest priority)

When the same server name exists in multiple scopes, the higher-priority scope wins. Use --scope flags to target a specific scope when adding, removing, enabling, or disabling servers.

TUI Settings¶

MCP servers can also be managed through the interactive TUI settings editor (lango settings), which provides forms for adding and configuring servers with transport-specific fields.

Key Config Options¶

Key	Type	Default	Description
`mcp.enabled`	bool	`false`	Enable MCP integration
`mcp.defaultTimeout`	duration	`30s`	Default server connection timeout
`mcp.maxOutputTokens`	int	`25000`	Max output tokens for MCP tool results
`mcp.servers.<name>`	object		Server configuration (set via `lango mcp add` or JSON files)

Tool Naming Convention¶

Tools discovered from MCP servers are registered with the naming pattern:

mcp__{serverName}__{toolName}

For example, a read_file tool from a server named filesystem becomes mcp__filesystem__read_file.