Mcpcall

mcpcall

Convert any MCP server into a self-contained Claude Code skill with a Python wrapper in scripts/mcpcall.py.

Each MCP skill bundles its own scripts/mcpcall.py with the server URL baked in. No shared dependency, no cross-skill references — fully portable. Uses httpx (respects http_proxy/https_proxy) and MCP Streamable HTTP transport. Dependencies resolved by uv on first run via PEP 723 inline metadata.

The script is executable (chmod +x) with a #!/usr/bin/env -S uv run --script shebang, so it can be called directly without any prefix.

Quick Start

1. Create skill directory with scripts/ subfolder
2. Copy the appropriate template into scripts/mcpcall.py:
   • No auth needed → references/template-noauth.py
   • API key required → references/template-auth.py
3. chmod +x scripts/mcpcall.py
4. Edit the constants at the top of the script
5. Discover tools: scripts/mcpcall.py --list
6. Write SKILL.md with tool docs

Step 1: Copy and Configure the Script

No-auth variant

Edit SERVER_URL:

SERVER_URL = "https://mcp.example.com/v1"

Auth variant

Edit both constants:

SERVER_URL = "https://mcp.example.com/v1"
ENV_VAR = "MY_API_KEY"

The script reads the API key from the environment variable at runtime — fully stateless.

Step 2: Write SKILL.md

Frontmatter

---
name: my-mcp-skill
description: <what it does>. TRIGGER when <when to activate>.
allowed-tools:
  - Bash(*mcpcall.py*:*)
---

• name — kebab-case, matches directory name.
• description — concise capability + explicit TRIGGER clause.
• allowed-tools — glob pattern auto-approving mcpcall invocations.

Body

# My MCP Skill

<one-line description>. No API key required.

## Setup (auth variant only)

Requires `MY_API_KEY` environment variable:

```bash
export MY_API_KEY=<key>
```

## tool_name
<description>
- `param` (required): <what it is>

```bash
${CLAUDE_PLUGIN_ROOT}/scripts/mcpcall.py tool_name param:"value"
```

Argument Styles

Key-value — flat parameters (strings, numbers, booleans):

${CLAUDE_PLUGIN_ROOT}/scripts/mcpcall.py search query:"search terms" num:10 verbose:true

Type coercion: true/false → bool, integers → int, floats → float, else string.

JSON — arrays or objects:

${CLAUDE_PLUGIN_ROOT}/scripts/mcpcall.py classify --args '{"texts": ["a", "b"], "labels": ["x", "y"]}'

Both can be combined — kv_args as base, --args JSON merged on top.

Skill Directory Layout

my-mcp-skill/
├── SKILL.md              # frontmatter + tool docs
└── scripts/
    └── mcpcall.py        # self-contained PEP 723 script (chmod +x)

Live Examples