A CLI host application that enables Large Language Models (LLMs) to interact with external tools through the Model Context Protocol (MCP). Currently supports both Claude 3.5 Sonnet and Ollama models.
Discuss the Project on Discord
MCPHost acts as a host in the MCP client-server architecture, where:
- Hosts (like MCPHost) are LLM applications that manage connections and interactions
- Clients maintain 1:1 connections with MCP servers
- Servers provide context, tools, and capabilities to the LLMs
This architecture allows language models to:
- Access external tools and data sources π οΈ
- Maintain consistent context across interactions π
- Execute commands and retrieve information safely π
Currently supports:
- Claude 3.5 Sonnet (claude-3-5-sonnet-20240620)
- Any Ollama-compatible model with function calling support
- Google Gemini models
- Any OpenAI-compatible local or online model with function calling support
- Interactive conversations with support models
- Non-interactive mode for scripting and automation
- Script mode for executable YAML-based automation scripts
- Support for multiple concurrent MCP servers
- Tool filtering with
allowedTools
andexcludedTools
per server - Dynamic tool discovery and integration
- Tool calling capabilities for both model types
- Configurable MCP server locations and arguments
- Consistent command interface across model types
- Configurable message history window for context management
- Go 1.23 or later
- For OpenAI/Anthropic: API key for the respective provider
- For Ollama: Local Ollama installation with desired models
- For Google/Gemini: Google API key (see https://aistudio.google.com/app/apikey)
- One or more MCP-compatible tool servers
- API Keys:
# For all providers (use --provider-api-key flag or these environment variables)
export OPENAI_API_KEY='your-openai-key' # For OpenAI
export ANTHROPIC_API_KEY='your-anthropic-key' # For Anthropic
export GOOGLE_API_KEY='your-google-key' # For Google/Gemini
- Ollama Setup:
- Install Ollama from https://ollama.ai
- Pull your desired model:
ollama pull mistral
- Ensure Ollama is running:
ollama serve
You can also configure the Ollama client using standard environment variables, such as OLLAMA HOST
for the Ollama base URL.
- Google API Key (for Gemini):
export GOOGLE_API_KEY='your-api-key'
- OpenAI Compatible Setup:
- Get your API server base URL, API key and model name
- Use
--provider-url
and--provider-api-key
flags or set environment variables
go install github.com/mark3labs/mcphost@latest
MCPHost will automatically create a configuration file in your home directory if it doesn't exist. It looks for config files in this order:
.mcphost.yml
or.mcphost.json
(preferred).mcp.yml
or.mcp.json
(backwards compatibility)
Config file locations by OS:
- Linux/macOS:
~/.mcphost.yml
,~/.mcphost.json
,~/.mcp.yml
,~/.mcp.json
- Windows:
%USERPROFILE%\.mcphost.yml
,%USERPROFILE%\.mcphost.json
,%USERPROFILE%\.mcp.yml
,%USERPROFILE%\.mcp.json
You can also specify a custom location using the --config
flag.
MCPHost supports environment variable substitution in both config files and script frontmatter using the syntax:
${env://VAR}
- Required environment variable (fails if not set)${env://VAR:-default}
- Optional environment variable with default value
This allows you to keep sensitive information like API keys in environment variables while maintaining flexible configuration.
Example:
mcpServers:
github:
type: local
command: ["docker", "run", "-i", "--rm", "-e", "GITHUB_PERSONAL_ACCESS_TOKEN=${env://GITHUB_TOKEN}", "ghcr.io/github/github-mcp-server"]
environment:
DEBUG: "${env://DEBUG:-false}"
LOG_LEVEL: "${env://LOG_LEVEL:-info}"
model: "${env://MODEL:-anthropic:claude-sonnet-4-20250514}"
provider-api-key: "${env://OPENAI_API_KEY}" # Required - will fail if not set
Usage:
# Set required environment variables
export GITHUB_TOKEN="ghp_your_token_here"
export OPENAI_API_KEY="your_openai_key"
# Optionally override defaults
export DEBUG="true"
export MODEL="openai:gpt-4"
# Run mcphost
mcphost
MCPHost now supports a simplified configuration schema with three server types:
For local MCP servers that run commands on your machine:
{
"mcpServers": {
"filesystem": {
"type": "local",
"command": ["npx", "@modelcontextprotocol/server-filesystem", "${env://WORK_DIR:-/tmp}"],
"environment": {
"DEBUG": "${env://DEBUG:-false}",
"LOG_LEVEL": "${env://LOG_LEVEL:-info}",
"API_TOKEN": "${env://FS_API_TOKEN}"
},
"allowedTools": ["read_file", "write_file"],
"excludedTools": ["delete_file"]
},
"github": {
"type": "local",
"command": ["docker", "run", "-i", "--rm", "-e", "GITHUB_PERSONAL_ACCESS_TOKEN=${env://GITHUB_TOKEN}", "ghcr.io/github/github-mcp-server"],
"environment": {
"DEBUG": "${env://DEBUG:-false}"
}
},
"sqlite": {
"type": "local",
"command": ["uvx", "mcp-server-sqlite", "--db-path", "${env://DB_PATH:-/tmp/foo.db}"],
"environment": {
"SQLITE_DEBUG": "${env://DEBUG:-0}",
"DATABASE_URL": "${env://DATABASE_URL:-sqlite:///tmp/foo.db}"
}
}
}
}
Each local server entry requires:
type
: Must be set to"local"
command
: Array containing the command and all its argumentsenvironment
: (Optional) Object with environment variables as key-value pairsallowedTools
: (Optional) Array of tool names to include (whitelist)excludedTools
: (Optional) Array of tool names to exclude (blacklist)
For remote MCP servers accessible via HTTP:
{
"mcpServers": {
"websearch": {
"type": "remote",
"url": "${env://WEBSEARCH_URL:-https://api.example.com/mcp}",
"headers": ["Authorization: Bearer ${env://WEBSEARCH_TOKEN}"]
},
"weather": {
"type": "remote",
"url": "${env://WEATHER_URL:-https://weather-mcp.example.com}"
}
}
}
Each remote server entry requires:
type
: Must be set to"remote"
url
: The URL where the MCP server is accessibleheaders
: (Optional) Array of HTTP headers for authentication and custom headers
Remote servers automatically use the StreamableHTTP transport for optimal performance.
For builtin MCP servers that run in-process for optimal performance:
{
"mcpServers": {
"filesystem": {
"type": "builtin",
"name": "fs",
"options": {
"allowed_directories": ["${env://WORK_DIR:-/tmp}", "${env://HOME}/documents"]
},
"allowedTools": ["read_file", "write_file", "list_directory"]
},
"filesystem-cwd": {
"type": "builtin",
"name": "fs"
}
}
}
Each builtin server entry requires:
type
: Must be set to"builtin"
name
: Internal name of the builtin server (e.g.,"fs"
for filesystem)options
: Configuration options specific to the builtin server
Available Builtin Servers:
fs
(filesystem): Secure filesystem access with configurable allowed directoriesallowed_directories
: Array of directory paths that the server can access (defaults to current working directory if not specified)
bash
: Execute bash commands with security restrictions and timeout controls- No configuration options required
todo
: Manage ephemeral todo lists for task tracking during sessions- No configuration options required (todos are stored in memory and reset on restart)
fetch
: Fetch web content and convert to text, markdown, or HTML formats- No configuration options required
{
"mcpServers": {
"filesystem": {
"type": "builtin",
"name": "fs",
"options": {
"allowed_directories": ["/tmp", "/home/user/documents"]
}
},
"bash-commands": {
"type": "builtin",
"name": "bash"
},
"task-manager": {
"type": "builtin",
"name": "todo"
},
"web-fetcher": {
"type": "builtin",
"name": "fetch"
}
}
}
All MCP server types support tool filtering to restrict which tools are available:
allowedTools
: Whitelist - only specified tools are available from the serverexcludedTools
: Blacklist - all tools except specified ones are available
{
"mcpServers": {
"filesystem-readonly": {
"type": "builtin",
"name": "fs",
"allowedTools": ["read_file", "list_directory"]
},
"filesystem-safe": {
"type": "local",
"command": ["npx", "@modelcontextprotocol/server-filesystem", "/tmp"],
"excludedTools": ["delete_file"]
}
}
}
Note: allowedTools
and excludedTools
are mutually exclusive - you can only use one per server.
MCPHost maintains full backward compatibility with the previous configuration format. Note: A recent bug fix improved legacy stdio transport reliability for external MCP servers (Docker, NPX, etc.).
{
"mcpServers": {
"sqlite": {
"command": "uvx",
"args": ["mcp-server-sqlite", "--db-path", "/tmp/foo.db"],
"env": {
"DEBUG": "true"
}
}
}
}
{
"mcpServers": {
"server_name": {
"url": "http://some_host:8000/sse",
"headers": ["Authorization: Bearer my-token"]
}
}
}
{
"mcpServers": {
"phalcon": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"ghcr.io/mark3labs/phalcon-mcp:latest",
"serve"
]
}
}
}
{
"mcpServers": {
"websearch": {
"transport": "streamable",
"url": "https://api.example.com/mcp",
"headers": ["Authorization: Bearer your-api-token"]
}
}
}
MCPHost supports four transport types:
stdio
: Launches a local process and communicates via stdin/stdout (used by"local"
servers)sse
: Connects to a server using Server-Sent Events (legacy format)streamable
: Connects to a server using Streamable HTTP protocol (used by"remote"
servers)inprocess
: Runs builtin servers in-process for optimal performance (used by"builtin"
servers)
The simplified schema automatically maps:
"local"
type βstdio
transport"remote"
type βstreamable
transport"builtin"
type βinprocess
transport
You can specify a custom system prompt using the --system-prompt
flag. You can either:
-
Pass the prompt directly as text:
mcphost --system-prompt "You are a helpful assistant that responds in a friendly tone."
-
Pass a path to a text file containing the prompt:
mcphost --system-prompt ./prompts/assistant.md
Example
assistant.md
file:You are a helpful coding assistant. Please: - Write clean, readable code - Include helpful comments - Follow best practices - Explain your reasoning
Usage:
mcphost --system-prompt ./my-system-prompt.json
MCPHost is a CLI tool that allows you to interact with various AI models through a unified interface. It supports various tools through MCP servers and can run in both interactive and non-interactive modes.
Start an interactive conversation session:
mcphost
Run executable YAML-based automation scripts with variable substitution support:
# Using the script subcommand
mcphost script myscript.sh
# With variables
mcphost script myscript.sh --args:directory /tmp --args:name "John"
# Direct execution (if executable and has shebang)
./myscript.sh
Scripts combine YAML configuration with prompts in a single executable file. The configuration must be wrapped in frontmatter delimiters (---
). You can either include the prompt in the YAML configuration or place it after the closing frontmatter delimiter:
#!/usr/bin/env -S mcphost script
---
# This script uses the container-use MCP server from https://github.com/dagger/container-use
mcpServers:
container-use:
type: "local"
command: ["cu", "stdio"]
prompt: |
Create 2 variations of a simple hello world app using Flask and FastAPI.
Each in their own environment. Give me the URL of each app
---
Or alternatively, omit the prompt:
field and place the prompt after the frontmatter:
#!/usr/bin/env -S mcphost script
---
# This script uses the container-use MCP server from https://github.com/dagger/container-use
mcpServers:
container-use:
type: "local"
command: ["cu", "stdio"]
---
Create 2 variations of a simple hello world app using Flask and FastAPI.
Each in their own environment. Give me the URL of each app
Scripts support both environment variable substitution and script argument substitution:
- Environment Variables:
${env://VAR}
and${env://VAR:-default}
- Processed first - Script Arguments:
${variable}
and${variable:-default}
- Processed after environment variables
Variables can be provided via command line arguments:
# Script with variables
mcphost script myscript.sh --args:directory /tmp --args:name "John"
MCPHost supports these variable syntaxes:
- Required Environment Variables:
${env://VAR}
- Must be set in environment - Optional Environment Variables:
${env://VAR:-default}
- Uses default if not set - Required Script Arguments:
${variable}
- Must be provided via--args:variable value
- Optional Script Arguments:
${variable:-default}
- Uses default if not provided
Example script with mixed environment variables and script arguments:
#!/usr/bin/env -S mcphost script
---
mcpServers:
github:
type: "local"
command: ["gh", "api"]
environment:
GITHUB_TOKEN: "${env://GITHUB_TOKEN}"
DEBUG: "${env://DEBUG:-false}"
filesystem:
type: "local"
command: ["npx", "-y", "@modelcontextprotocol/server-filesystem", "${env://WORK_DIR:-/tmp}"]
model: "${env://MODEL:-anthropic:claude-sonnet-4-20250514}"
---
Hello ${name:-World}! Please list ${repo_type:-public} repositories for user ${username}.
Working directory is ${env://WORK_DIR:-/tmp}.
Use the ${command:-gh} command to fetch ${count:-10} repositories.
# Set environment variables first
export GITHUB_TOKEN="ghp_your_token_here"
export DEBUG="true"
export WORK_DIR="/home/user/projects"
# Uses env vars and defaults: name="World", repo_type="public", command="gh", count="10"
mcphost script myscript.sh
# Override specific script arguments
mcphost script myscript.sh --args:name "John" --args:username "alice"
# Override multiple script arguments
mcphost script myscript.sh --args:name "John" --args:username "alice" --args:repo_type "private"
# Mix of env vars, provided args, and default values
mcphost script myscript.sh --args:name "Alice" --args:command "gh api" --args:count "5"
- Empty defaults:
${var:-}
- Uses empty string if not provided - Complex defaults:
${path:-/tmp/default/path}
- Supports paths, URLs, etc. - Spaces in defaults:
${msg:-Hello World}
- Supports spaces in default values - Backward compatibility: Existing
${variable}
syntax continues to work unchanged
Important:
- Environment variables without defaults (e.g.,
${env://GITHUB_TOKEN}
) are required and must be set in the environment - Script arguments without defaults (e.g.,
${username}
) are required and must be provided via--args:variable value
syntax - Variables with defaults are optional and will use their default value if not provided
- Environment variables are processed first, then script arguments
- Executable: Use shebang line for direct execution (
#!/usr/bin/env -S mcphost script
) - YAML Configuration: Define MCP servers directly in the script
- Embedded Prompts: Include the prompt in the YAML
- Variable Substitution: Use
${variable}
and${variable:-default}
syntax with--args:variable value
- Variable Validation: Missing required variables cause script to exit with helpful error
- Interactive Mode: If prompt is empty, drops into interactive mode (handy for setup scripts)
- Config Fallback: If no
mcpServers
defined, uses default config - Tool Filtering: Supports
allowedTools
/excludedTools
per server - Clean Exit: Automatically exits after completion
Note: The shebang line requires env -S
to handle the multi-word command mcphost script
. This is supported on most modern Unix-like systems.
See examples/scripts/
for sample scripts:
example-script.sh
- Script with custom MCP serverssimple-script.sh
- Script using default config fallback
Run a single prompt and exit - perfect for scripting and automation:
# Basic non-interactive usage
mcphost -p "What is the weather like today?"
# Quiet mode - only output the AI response (no UI elements)
mcphost -p "What is 2+2?" --quiet
# Use with different models
mcphost -m ollama:qwen2.5:3b -p "Explain quantum computing" --quiet
MCPHost supports fine-tuning model behavior through various parameters:
# Control response length
mcphost -p "Explain AI" --max-tokens 1000
# Adjust creativity (0.0 = focused, 1.0 = creative)
mcphost -p "Write a story" --temperature 0.9
# Control diversity with nucleus sampling
mcphost -p "Generate ideas" --top-p 0.8
# Limit token choices for more focused responses
mcphost -p "Answer precisely" --top-k 20
# Set custom stop sequences
mcphost -p "Generate code" --stop-sequences "```","END"
These parameters work with all supported providers (OpenAI, Anthropic, Google, Ollama) where supported by the underlying model.
Models can be specified using the --model
(-m
) flag:
- Anthropic Claude (default):
anthropic:claude-3-5-sonnet-latest
- OpenAI or OpenAI-compatible:
openai:gpt-4
- Ollama models:
ollama:modelname
- Google:
google:gemini-2.0-flash
# Use Ollama with Qwen model
mcphost -m ollama:qwen2.5:3b
# Use OpenAI's GPT-4
mcphost -m openai:gpt-4
# Use OpenAI-compatible model with custom URL and API key
mcphost --model openai:<your-model-name> \
--provider-url <your-base-url> \
--provider-api-key <your-api-key>
# Single prompt with full UI
mcphost -p "List files in the current directory"
# Compact mode for cleaner output without fancy styling
mcphost -p "List files in the current directory" --compact
# Quiet mode for scripting (only AI response output, no UI elements)
mcphost -p "What is the capital of France?" --quiet
# Use in shell scripts
RESULT=$(mcphost -p "Calculate 15 * 23" --quiet)
echo "The answer is: $RESULT"
# Pipe to other commands
mcphost -p "Generate a random UUID" --quiet | tr '[:lower:]' '[:upper:]'
--provider-url string
: Base URL for the provider API (applies to OpenAI, Anthropic, Ollama, and Google)--provider-api-key string
: API key for the provider (applies to OpenAI, Anthropic, and Google)--config string
: Config file location (default is $HOME/.mcphost.yml)--system-prompt string
: system-prompt file location--debug
: Enable debug logging--max-steps int
: Maximum number of agent steps (0 for unlimited, default: 0)-m, --model string
: Model to use (format: provider:model) (default "anthropic:claude-sonnet-4-20250514")-p, --prompt string
: Run in non-interactive mode with the given prompt--quiet
: Suppress all output except the AI response (only works with --prompt)--compact
: Enable compact output mode without fancy styling (ideal for scripting and automation)--stream
: Enable streaming responses (default: true, use--stream=false
to disable)
mcphost auth login anthropic
: Authenticate with Anthropic using OAuth (alternative to API keys)mcphost auth logout anthropic
: Remove stored OAuth credentialsmcphost auth status
: Show authentication status
Note: OAuth credentials (when present) take precedence over API keys from environment variables and --provider-api-key
flags.
--max-tokens int
: Maximum number of tokens in the response (default: 4096)--temperature float32
: Controls randomness in responses (0.0-1.0, default: 0.7)--top-p float32
: Controls diversity via nucleus sampling (0.0-1.0, default: 0.95)--top-k int32
: Controls diversity by limiting top K tokens to sample from (default: 40)--stop-sequences strings
: Custom stop sequences (comma-separated)
All command-line flags can be configured via the config file. MCPHost will look for configuration in this order:
~/.mcphost.yml
or~/.mcphost.json
(preferred)~/.mcp.yml
or~/.mcp.json
(backwards compatibility)
Example config file (~/.mcphost.yml
):
# MCP Servers - New Simplified Format
mcpServers:
filesystem-local:
type: "local"
command: ["npx", "@modelcontextprotocol/server-filesystem", "/path/to/files"]
environment:
DEBUG: "true"
filesystem-builtin:
type: "builtin"
name: "fs"
options:
allowed_directories: ["/tmp", "/home/user/documents"]
websearch:
type: "remote"
url: "https://api.example.com/mcp"
# Application settings
model: "anthropic:claude-sonnet-4-20250514"
max-steps: 20
debug: false
system-prompt: "/path/to/system-prompt.txt"
# Model generation parameters
max-tokens: 4096
temperature: 0.7
top-p: 0.95
top-k: 40
stop-sequences: ["Human:", "Assistant:"]
# Streaming configuration
stream: false # Disable streaming (default: true)
# API Configuration
provider-api-key: "your-api-key" # For OpenAI, Anthropic, or Google
provider-url: "https://api.openai.com/v1" # Custom base URL
Note: Command-line flags take precedence over config file values.
While chatting, you can use:
/help
: Show available commands/tools
: List all available tools/servers
: List configured MCP servers/history
: Display conversation history/quit
: Exit the applicationCtrl+C
: Exit at any time
Optional OAuth authentication for Anthropic (alternative to API keys):
mcphost auth login anthropic
: Authenticate using OAuthmcphost auth logout anthropic
: Remove stored OAuth credentialsmcphost auth status
: Show authentication status
--config
: Specify custom config file location
MCPHost's non-interactive mode makes it perfect for automation, scripting, and integration with other tools.
#!/bin/bash
# Get weather and save to file
mcphost -p "What's the weather in New York?" --quiet > weather.txt
# Process files with AI
for file in *.txt; do
summary=$(mcphost -p "Summarize this file: $(cat $file)" --quiet)
echo "$file: $summary" >> summaries.txt
done
# Code review automation
DIFF=$(git diff HEAD~1)
mcphost -p "Review this code diff and suggest improvements: $DIFF" --quiet
# Generate release notes
COMMITS=$(git log --oneline HEAD~10..HEAD)
mcphost -p "Generate release notes from these commits: $COMMITS" --quiet
# Process CSV data
mcphost -p "Analyze this CSV data and provide insights: $(cat data.csv)" --quiet
# Generate reports
mcphost -p "Create a summary report from this JSON: $(cat metrics.json)" --quiet
# Use as a microservice
curl -X POST http://localhost:8080/process \
-d "$(mcphost -p 'Generate a UUID' --quiet)"
- Use
--quiet
flag to get clean output suitable for parsing (only AI response, no UI) - Use
--compact
flag for simplified output without fancy styling (when you want to see UI elements) - Note:
--compact
and--quiet
are mutually exclusive ---compact
has no effect with--quiet
- Use environment variables for sensitive data like API keys instead of hardcoding them
- Use
${env://VAR}
syntax in config files and scripts for environment variable substitution - Combine with standard Unix tools (
grep
,awk
,sed
, etc.) - Set appropriate timeouts for long-running operations
- Handle errors appropriately in your scripts
- Use environment variables for API keys in production
# Set sensitive variables in environment
export GITHUB_TOKEN="ghp_your_token_here"
export OPENAI_API_KEY="your_openai_key"
export DATABASE_URL="postgresql://user:pass@localhost/db"
# Use in config files
mcpServers:
github:
environment:
GITHUB_TOKEN: "${env://GITHUB_TOKEN}"
DEBUG: "${env://DEBUG:-false}"
# Use in scripts
mcphost script my-script.sh --args:username alice
MCPHost can work with any MCP-compliant server. For examples and reference implementations, see the MCP Servers Repository.
Contributions are welcome! Feel free to:
- Submit bug reports or feature requests through issues
- Create pull requests for improvements
- Share your custom MCP servers
- Improve documentation
Please ensure your contributions follow good coding practices and include appropriate tests.
This project is licensed under the MIT License - see the LICENSE file for details.
- Thanks to the Anthropic team for Claude and the MCP specification
- Thanks to the Ollama team for their local LLM runtime
- Thanks to all contributors who have helped improve this tool