bellwether discover
Quick discovery of MCP server capabilities without running checks.
Synopsis
bellwether discover [command] [args...] [options]
Description
The discover command connects to an MCP server and lists its capabilities (tools, prompts, resources, and resource templates) without conducting a full check. This is useful for quick reconnaissance or verifying server connectivity.
Config Optional
discover can run without a config file. If bellwether.yaml is present, its discovery settings are used.
For remote MCP servers, use --transport sse or --transport streamable-http with --url instead of providing a command.
Arguments
| Argument | Description |
|---|---|
[command] | Command to start the MCP server (not required for remote) |
[args...] | Arguments to pass to the server command |
Options
Output Options
| Option | Description | Default |
|---|---|---|
-c, --config <path> | Path to config file | bellwether.yaml |
--json | Output as JSON | false |
--timeout <ms> | Connection timeout in milliseconds | discovery.timeout |
Remote Server Options
| Option | Description | Default |
|---|---|---|
--transport <type> | Transport type: stdio, sse, streamable-http | discovery.transport |
--url <url> | URL for remote MCP server (requires --transport sse or streamable-http) | - |
--session-id <id> | Session ID for remote MCP session continuity (optional) | - |
-H, --header <header...> | Custom header(s) for remote MCP requests | From discovery.headers / server.headers |
Examples
Basic Discovery
# Discover filesystem server capabilities
bellwether discover npx @modelcontextprotocol/server-filesystem /tmp
Output:
╔════════════════════════════════════════════════════════════════╗
║ @modelcontextprotocol/server-filesystem v1.0.0 ║
║ Protocol Version: 2025-11-25 ║
╚════════════════════════════════════════════════════════════════╝
CAPABILITIES
4 Tools · Resources
──────────────────────────────────────────────────────────────────
TOOLS
──────────────────────────────────────────────────────────────────
read_file(path)
Read contents of a file
write_file(path, content)
Write content to a file
list_directory(path)
List directory contents
search_files(pattern, path?)
Search for files matching a pattern
──────────────────────────────────────────────────────────────────
QUICK START
──────────────────────────────────────────────────────────────────
bellwether check npx @modelcontextprotocol/server-filesystem /tmp
Schema validation (free, fast)
bellwether explore npx @modelcontextprotocol/server-filesystem /tmp
Deep behavioral exploration (requires LLM)
JSON Output
bellwether discover --json npx @modelcontextprotocol/server-memory
Output:
{
"serverInfo": {
"name": "@modelcontextprotocol/server-memory",
"version": "1.0.0"
},
"tools": [
{
"name": "store",
"description": "Store a value in memory",
"inputSchema": {
"type": "object",
"properties": {
"key": { "type": "string" },
"value": { "type": "any" }
},
"required": ["key", "value"]
}
}
],
"prompts": [],
"resources": []
}
With Custom Timeout
# Increase timeout for slow servers
bellwether discover --timeout 60000 npx slow-server
Remote MCP Servers
# Discover capabilities of a remote server via SSE
bellwether discover \
--transport sse \
--url https://api.example.com/mcp
# With authentication
bellwether discover \
--transport streamable-http \
--url https://api.example.com/mcp \
-H "Authorization: Bearer $MCP_SERVER_TOKEN"
For config-based auth, set:
server:
headers:
Authorization: "Bearer ${MCP_SERVER_TOKEN}"
discovery:
headers:
X-API-Key: "${MCP_API_KEY}" # Overrides server.headers for discover
Use Cases
Verify Server Connectivity
Before running a full check, verify the server starts and responds:
bellwether discover npx your-server && echo "Server OK"
List Available Tools
Get a quick overview of what a server can do:
bellwether discover npx @modelcontextprotocol/server-postgres
Generate Tool Inventory
Create a JSON inventory of server capabilities:
bellwether discover --json npx your-server > capabilities.json
Debugging Server Issues
Use discover to isolate connection vs. check issues:
# If this fails, it's a connection issue
bellwether discover npx your-server
# If discover works but check fails, review the check output
bellwether check npx your-server
Exit Codes
| Code | Meaning |
|---|---|
0 | Success - server capabilities discovered |
4 | Error - connection failed or server error |