mcp-cli · diff
git:20260719.252ad11 to git:20260719.03668ce
1 added, 1 removed. Audit A to A.
---
name: mcp-cli
description: "Use when you need a one-off MCP server capability during research or debugging without permanently mounting it as a context-polluting integration."
allowed-tools: Read Bash
user-invocable: false
---
# MCP CLI (Transient MCP Access)
## Overview
The `mcp` CLI (from `github.com/f/mcptools`) discovers and invokes MCP server capabilities on-demand. Use it when a task needs ONE server's tool — a doc fetch, a single query, a quick lookup — instead of permanently mounting that server as an always-loaded integration.
This keeps accelerators **transient**: spun up for the task, used, and dropped. A permanently mounted MCP server costs context on every session whether you call it or not. The CLI costs nothing until you run it.
Composes with `cc10x:research`.
## Prerequisite (install once)
Check first: `command -v mcp`. If absent, install:
```bash
git clone https://github.com/f/mcptools /tmp/mcptools
CGO_ENABLED=0 go build -o ~/.local/bin/mcp /tmp/mcptools/cmd/mcptools
# ensure ~/.local/bin is on PATH
```
If `go` is unavailable, report that the accelerator is missing and proceed with built-in tools — do NOT treat the missing binary as a task blocker (it is a fallback message, not a wall).
## Flow: discover → call → release
- **1. Discover first — always.** Never call a tool whose schema you have not seen.
+ **1. Discover first — always.** Never call a tool whose schema you have not seen — guessed params fail silently or hit the wrong tool.
```bash
mcp tools <server-command> # list tools
mcp tools --format json <server-command> # full param schema for parsing
mcp resources <server-command> # list resources
mcp prompts <server-command> # list prompts
```
**2. Lead read-only when exploring.** Restrict the surface before you touch an unfamiliar server:
```bash
mcp guard --allow 'tools:read_*,list_*' --deny 'tools:write_*,delete_*' <server-command>
```
Drop the guard only once you know exactly which write you intend.
**3. Call** with params matching the discovered signature exactly (`param:str`, `param:num`, `[optional]`):
```bash
mcp call <tool_name> --params '<json>' -f json <server-command>
```
Output `-f json` for parsing, `-f pretty` for reading. Check exit code and stderr on failure — a non-zero exit is a real error, not a fallback message.
**Server-command examples:**
- stdio: `npx -y @modelcontextprotocol/server-filesystem /path`
- HTTP: pass the URL (auto-detected); SSE via `--transport sse`
- auth: `--auth-header "Bearer <token>"`, `--auth-user user:pass`, or `-e ENV_VAR` for docker servers
## Aliases (only for repeated use in one task)
If you call the same server several times, alias it; remove it when the task ends so nothing lingers:
```bash
mcp alias add <name> <server-command> # then: mcp tools <name>, mcp call ... <name>
mcp alias remove <name> # release when done
```
Aliases persist in `~/.mcpt/aliases.json`. Cleaning them up is part of keeping the accelerator transient.