mcp2cli

Skill by ara.so — MCP Skills collection.

mcp2cli converts any MCP server, OpenAPI specification, or GraphQL endpoint into a CLI at runtime without code generation. It dramatically reduces token consumption by replacing repeated tool schema transmissions with simple CLI calls — saving 96-99% of tokens on every LLM turn.

Installation

bash

# Run directly without installing
uvx mcp2cli --help

# Or install globally
uv tool install mcp2cli

# Install as a skill for AI agents
npx skills add knowsuchagency/mcp2cli --skill mcp2cli

Core Concepts

mcp2cli operates in four modes:

MCP HTTP/SSE: Connect to MCP servers over HTTP with SSE or streamable HTTP transport
MCP stdio: Launch and communicate with local MCP servers via stdio
OpenAPI: Generate CLI from OpenAPI 3.x specs (JSON or YAML)
GraphQL: Introspect and query GraphQL endpoints

All modes support:

Dynamic command generation (no codegen step)
Automatic caching with configurable TTL
OAuth 2.0 flows (authorization code + PKCE, client credentials)
Secret management (env vars, files)
Usage tracking and intelligent tool ranking

MCP HTTP Mode

Connect to MCP servers over HTTP with automatic transport negotiation:

bash

# List available tools
mcp2cli --mcp https://mcp.example.com/sse --list

# Call a tool
mcp2cli --mcp https://mcp.example.com/sse search --query "rust async"

# With authentication
mcp2cli --mcp https://mcp.example.com/sse \
  --auth-header "x-api-key:env:MCP_API_KEY" \
  query --sql "SELECT * FROM users LIMIT 10"

# Force specific transport (skip auto-negotiation)
mcp2cli --mcp https://mcp.example.com/sse --transport sse --list

# Search tools by name or description
mcp2cli --mcp https://mcp.example.com/sse --search "database"

MCP stdio Mode

Launch local MCP servers and communicate via stdio:

bash

# List tools from filesystem MCP server
mcp2cli --mcp-stdio "npx @modelcontextprotocol/server-filesystem /tmp" --list

# Read a file
mcp2cli --mcp-stdio "npx @modelcontextprotocol/server-filesystem /tmp" \
  read-file --path /tmp/data.json

# Pass environment variables to the server
mcp2cli --mcp-stdio "node ./custom-server.js" \
  --env DATABASE_URL=env:DATABASE_URL \
  --env DEBUG=1 \
  search --query "test"

OpenAPI Mode

Generate CLI from OpenAPI specifications:

bash

# Remote spec
mcp2cli --spec https://petstore3.swagger.io/api/v3/openapi.json --list

# Local spec with base URL override
mcp2cli --spec ./openapi.yaml --base-url https://api.example.com --list

# Call an endpoint
mcp2cli --spec ./openapi.json --base-url https://api.example.com \
  list-pets --status available --limit 20

# POST with JSON body from stdin
echo '{"name": "Fido", "species": "dog"}' | \
  mcp2cli --spec ./openapi.json create-pet --stdin

# With authentication
mcp2cli --spec ./openapi.json \
  --auth-header "Authorization:Bearer env:API_TOKEN" \
  create-item --name "New Item"

GraphQL Mode

Query GraphQL endpoints with automatic introspection:

bash

# List all queries and mutations
mcp2cli --graphql https://api.example.com/graphql --list

# Execute a query (auto-generates selection set)
mcp2cli --graphql https://api.example.com/graphql users --limit 10

# Execute a mutation
mcp2cli --graphql https://api.example.com/graphql \
  create-user --name "Alice" --email "alice@example.com"

# Override selection set fields
mcp2cli --graphql https://api.example.com/graphql \
  users --fields "id name email createdAt"

# With authentication
mcp2cli --graphql https://api.example.com/graphql \
  --auth-header "Authorization:Bearer env:GRAPHQL_TOKEN" \
  users

OAuth Authentication

All modes support OAuth 2.0 flows:

bash

# Authorization code + PKCE (opens browser)
mcp2cli --mcp https://mcp.example.com/sse --oauth --list
mcp2cli --spec https://api.example.com/openapi.json --oauth list-users
mcp2cli --graphql https://api.example.com/graphql --oauth users

# Client credentials (machine-to-machine)
mcp2cli --spec https://api.example.com/openapi.json \
  --oauth-client-id "env:OAUTH_CLIENT_ID" \
  --oauth-client-secret "env:OAUTH_CLIENT_SECRET" \
  list-resources

# With specific scopes
mcp2cli --graphql https://api.example.com/graphql \
  --oauth --oauth-scope "read:users write:users" \
  users

# Local spec — provide base URL for OAuth discovery
mcp2cli --spec ./openapi.json \
  --base-url https://api.example.com \
  --oauth \
  --list

Tokens are cached in

~/.cache/mcp2cli/oauth/

and automatically refreshed.

Secret Management

Avoid passing secrets as CLI arguments:

bash

# Read from environment variable
mcp2cli --mcp https://mcp.example.com/sse \
  --auth-header "Authorization:env:MY_API_TOKEN" \
  --list

# Read from file
mcp2cli --spec ./openapi.json \
  --oauth-client-secret "file:/run/secrets/client_secret" \
  --oauth-client-id "file:/run/secrets/client_id" \
  --list

# Works with secret managers
vault kv get -field=token secret/api | \
  MY_TOKEN=$(cat) mcp2cli --mcp https://mcp.example.com/sse \
  --auth-header "Authorization:env:MY_TOKEN" \
  search --query "data"

Bake Mode — Save Connection Settings

Create reusable named configurations:

bash

# Create baked tool from OpenAPI spec
mcp2cli bake create petstore \
  --spec https://api.example.com/openapi.json \
  --auth-header "Authorization:Bearer env:PETSTORE_TOKEN" \
  --exclude "delete-*,update-*" \
  --methods GET,POST \
  --cache-ttl 7200

# Create baked tool from MCP stdio server
mcp2cli bake create github \
  --mcp-stdio "npx @modelcontextprotocol/server-github" \
  --env GITHUB_TOKEN=env:GITHUB_TOKEN \
  --include "search-*,list-*" \
  --exclude "delete-*"

# Create baked tool from GraphQL endpoint
mcp2cli bake create hasura \
  --graphql https://hasura.example.com/v1/graphql \
  --auth-header "x-hasura-admin-secret:env:HASURA_SECRET"

# Use baked tool with @ prefix
mcp2cli @petstore --list
mcp2cli @petstore list-pets --limit 5
mcp2cli @github search-repos --query "mcp server"
mcp2cli @hasura users --limit 10

# Manage baked tools
mcp2cli bake list
mcp2cli bake show petstore
mcp2cli bake update petstore --cache-ttl 3600
mcp2cli bake remove petstore

# Install as standalone script
mcp2cli bake install petstore
# Creates ~/.local/bin/petstore wrapper

# Install to custom directory
mcp2cli bake install petstore --dir ./scripts/

Filtering Options

bash

# Include only specific tool patterns
mcp2cli bake create myapi \
  --spec ./openapi.json \
  --include "list-*,get-*,search-*"

# Exclude dangerous operations
mcp2cli bake create myapi \
  --spec ./openapi.json \
  --exclude "delete-*,destroy-*"

# Limit to specific HTTP methods (OpenAPI only)
mcp2cli bake create myapi \
  --spec ./openapi.json \
  --methods GET,POST

Usage-Aware Tool Ranking

Reduce token costs with intelligent tool ranking:

bash

# Default list (sorted by usage frequency when available)
mcp2cli @myapi --list

# Top 10 most-used tools, compact output (~20 tokens)
mcp2cli @myapi --list --top 10 --compact

# Sort by most recently used
mcp2cli @myapi --list --sort recent

# Alphabetical sort
mcp2cli @myapi --list --sort alpha

# Show full descriptions
mcp2cli @myapi --list --verbose

Usage data is tracked locally in

~/.cache/mcp2cli/usage.json

Output Control

bash

# Pretty-print JSON (auto-enabled for TTY)
mcp2cli --spec ./openapi.json --pretty list-users

# Raw response body (no JSON parsing)
mcp2cli --spec ./openapi.json --raw get-binary-data

# Limit output to first N records
mcp2cli --spec ./openapi.json list-logs --head 20

# TOON output (40-60% fewer tokens for LLMs)
mcp2cli --mcp https://mcp.example.com/sse --toon list-large-dataset

# Pipe-friendly output
mcp2cli --spec ./openapi.json list-users | jq '.[] | .email'

Caching

Control spec and tool list caching:

bash

# Force refresh (bypass cache)
mcp2cli --spec https://api.example.com/openapi.json --refresh --list

# Custom TTL (7 days)
mcp2cli --spec https://api.example.com/openapi.json --cache-ttl 604800 --list

# Custom cache key
mcp2cli --spec https://api.example.com/openapi.json --cache-key prod-api --list

# Override cache directory
MCP2CLI_CACHE_DIR=/tmp/my-cache mcp2cli --spec ./openapi.json --list

Default cache location:

~/.cache/mcp2cli/

Default TTL: 3600 seconds (1 hour)

Common Patterns

Create a Skill from an API

bash

# Generate a skill configuration for an OpenAPI service
mcp2cli --spec https://api.example.com/openapi.json --list

# Create baked tool for easier access
mcp2cli bake create myservice \
  --spec https://api.example.com/openapi.json \
  --auth-header "Authorization:Bearer env:MYSERVICE_TOKEN"

# Use in skill workflows
mcp2cli @myservice list-resources --format json | jq '.[] | select(.active == true)'

Multi-Environment Setup

bash

# Development environment
mcp2cli bake create myapi-dev \
  --spec https://dev-api.example.com/openapi.json \
  --auth-header "Authorization:Bearer env:DEV_TOKEN"

# Production environment
mcp2cli bake create myapi-prod \
  --spec https://api.example.com/openapi.json \
  --auth-header "Authorization:Bearer env:PROD_TOKEN"

# Use environment-specific tools
mcp2cli @myapi-dev test-endpoint --data "test"
mcp2cli @myapi-prod get-metrics --period "24h"

Chaining with MCP Servers

bash

# Use filesystem MCP to read config, then call API
CONFIG=$(mcp2cli --mcp-stdio "npx @modelcontextprotocol/server-filesystem /etc" \
  read-file --path /etc/myapp/config.json)

echo "$CONFIG" | jq -r '.api_endpoint' | \
  xargs -I {} mcp2cli --spec {}/openapi.json --list

Filtering Large Tool Lists

bash

# Search tools related to users
mcp2cli @myapi --search "user"

# List only creation operations
mcp2cli @myapi --list | grep "^create-"

# Get compact list of top tools for LLM context
mcp2cli @myapi --list --top 20 --compact

Python API Usage

While mcp2cli is primarily a CLI tool, you can use its components programmatically:

python

from mcp2cli.openapi import load_spec
from mcp2cli.client import make_request
import asyncio

async def call_api():
    # Load OpenAPI spec
    spec = await load_spec("https://api.example.com/openapi.json")
    
    # Make request
    response = await make_request(
        spec=spec,
        operation_id="listPets",
        params={"limit": 10},
        auth_headers={"Authorization": "Bearer token"}
    )
    
    return response

result = asyncio.run(call_api())

Troubleshooting

OAuth Flow Fails

bash

# Clear cached tokens
rm -rf ~/.cache/mcp2cli/oauth/

# Retry with verbose output
mcp2cli --spec ./openapi.json --oauth --list --verbose

MCP Server Connection Issues

bash

# Test transport explicitly
mcp2cli --mcp https://mcp.example.com/sse --transport sse --list
mcp2cli --mcp https://mcp.example.com/sse --transport streamable --list

# Check server logs if using stdio
mcp2cli --mcp-stdio "npx @modelcontextprotocol/server-filesystem /tmp" \
  --env DEBUG=* \
  --list

Cache Issues

bash

# Force refresh
mcp2cli --spec ./openapi.json --refresh --list

# Clear all cache
rm -rf ~/.cache/mcp2cli/

# Use temporary cache location
MCP2CLI_CACHE_DIR=/tmp/test-cache mcp2cli --spec ./openapi.json --list

Tool Not Found After Baking

bash

# Check baked tool exists
mcp2cli bake list

# Verify configuration
mcp2cli bake show myapi

# Recreate with explicit filters
mcp2cli bake update myapi --include "*"

Large Response Truncation

bash

# Use --head to limit records
mcp2cli @myapi list-all --head 100

# Use --raw to get full response
mcp2cli @myapi list-all --raw > output.json

# Use TOON for token efficiency
mcp2cli @myapi list-all --toon

Configuration

Configuration directory:

~/.config/mcp2cli/

Cache directory:

~/.cache/mcp2cli/

Override with environment variables:

```
MCP2CLI_CONFIG_DIR
```
: Configuration directory
```
MCP2CLI_CACHE_DIR
```
: Cache directory

Baked tools are stored in

~/.config/mcp2cli/baked.json

Usage tracking in

~/.cache/mcp2cli/usage.json

OAuth tokens in

~/.cache/mcp2cli/oauth/

mcp2cli-api-to-cli

NPX Install

Tags

SKILL.md Content

mcp2cli

Installation

Core Concepts

MCP HTTP Mode

MCP stdio Mode

OpenAPI Mode

GraphQL Mode

OAuth Authentication

Secret Management

Bake Mode — Save Connection Settings

Filtering Options

Usage-Aware Tool Ranking

Output Control

Caching

Common Patterns

Create a Skill from an API

Multi-Environment Setup

Chaining with MCP Servers

Filtering Large Tool Lists

Python API Usage

Troubleshooting

OAuth Flow Fails

MCP Server Connection Issues

Cache Issues

Tool Not Found After Baking

Large Response Truncation

Configuration