MCP Servers

Hamr supports MCP (Model Context Protocol) servers for extending tool capabilities.

Configuration

MCP servers are configured in [mcp.servers]:

[mcp.servers.context7]
enabled = true
command = "npx"
args = ["-y", "@upstash/context7-mcp"]

[mcp.servers.filesystem]
enabled = false
command = "npx"
args = ["-y", "@modelcontextprotocol/server-filesystem", "."]

Server Fields

Field	Type	Required	Description
enabled	boolean	No (default: true)	Whether the server starts with Hamr
command	string	Yes	The command to launch the server
args	string[]	No	Command arguments
env	object	No	Environment variables for the server process

Environment Variables

[mcp.servers.github]
enabled = true
command = "npx"
args = ["-y", "@modelcontextprotocol/server-github"]

[mcp.servers.github.env]
GITHUB_TOKEN = "${GITHUB_TOKEN}"

Managing MCP Servers in the TUI

Press / and type mcp to open the MCP tab in settings:

• ✓ context7 — Enabled, shows npx -y @upstash/context7-mcp
• ○ filesystem — Disabled
• ! github — Missing GITHUB_TOKEN env var

Press Space or Enter to toggle a server on/off.

Context7 MCP Example

Add to .hamr.toml:

[mcp.servers.context7]
enabled = true
command = "npx"
args = ["-y", "@upstash/context7-mcp"]

This gives Hamr access to up-to-date library documentation during coding tasks.

Validation

Hamr validates MCP configurations:

• Missing command → error shown in settings
• Missing environment variables that contain TOKEN → warning shown
• Invalid JSON schema → server marked as broken

Limitations (Current)

• MCP tool import is guarded and requires explicit policy approval
• Servers are validated on startup but not auto-started yet
• Server process management is planned for a future release