Discover, inspect, call

Agents load only what they need. The complete catalog of tool schemas is not injected upfront.

npm install -g @bayway/janusmcp

janusmcp tools
janusmcp schema list_tables
janusmcp call list_tables --args '{"schemas":["public"]}'
janusmcp call ping --account client_b --json --timeout 30s

Compact discovery

tools returns names and short descriptions. Use --json only when full definitions are required.

One schema at a time

schema <tool> provides the exact input contract immediately before a call.

Stable automation

call --json, opt-in timeouts and documented exit codes make agent loops predictable.

Accounts, profiles and reuse

janusmcp status
janusmcp use client_a                 # persist the default account/profile
janusmcp tools client_b               # inspect without changing the default
janusmcp call ping --account client_b # one-shot cross-account call

janusmcp daemon start                 # keep upstream sessions warm
janusmcp daemon status --json
janusmcp call ping                    # auto-detects the daemon
janusmcp call ping --direct           # bypasses it for this call

The managed daemon listens only on 127.0.0.1, requires a randomly generated local bearer token and remains optional. Direct one-shot mode is always available.

Instructions for an AI agent

Copy this into your project instructions or agent skill:

Use JanusMCP from the shell for external tools.
1. Run `janusmcp tools [account-or-profile]` to discover relevant tools.
2. Run `janusmcp schema <tool> --account <selector>` before the first call.
3. Invoke with `janusmcp call <tool> --account <selector> --json --timeout 2m`.
4. Pass arguments through `--args '<json>'` or JSON on stdin.
5. Never guess a tool schema. Treat non-zero exit codes as failures and inspect stderr.

See the complete agent CLI guide.

Stable exit codes

Code	Meaning
0	Success
1	Unclassified error
2	Invalid syntax, flag or JSON input
3	Configuration, selector or tool lookup error
4	Credential or authentication error
5	Upstream connection or protocol error
6	The MCP tool returned `isError`
124	Timeout
130	Interrupted by signal