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fast-agent go

fast-agent go command

The go command allows you to run an interactive agent directly from the command line without creating a dedicated agent.py file.

Usage

fast-agent go [OPTIONS]

Options

  • --name TEXT: Name for the workflow (default: "FastAgent CLI")
  • --instruction, -i <path or url>: File name or URL for System Prompt (default: "You are a helpful AI Agent.")
  • --config-path, -c <path>: Path to config file
  • --servers <server1>,<server2>: Comma-separated list of server names to enable from config
  • --url TEXT: Comma-separated list of HTTP/SSE URLs to connect to directly
  • --auth TEXT: Bearer token for authorization with URL-based servers
  • --model <model_string>: Override the default model (e.g., haiku, sonnet, gpt-4)
  • --model <model_string1>,<model_string2>,...: Set up a parallel containing each model
  • --message, -m TEXT: Message to send to the agent (skips interactive mode)
  • --prompt-file, -p <path>: Path to a prompt file to use (either text or JSON)
  • --quiet: Disable progress display and logging
  • --stdio "<command> <options>": Run the command to attach a STDIO server (enclose arguments in quotes)
  • --npx "@package/name <options>": Run an NPX package as a STDIO server (enclose arguments in quotes)
  • --uvx "@package/name <options>": Run an UVX package as a STDIO server (enclose arguments in quotes)

Examples

Note - you may omit go when supplying command line options.

# Basic usage with interactive mode
fast-agent go --model=haiku

# Basic usage with interactive mode (go omitted)
fast-agent --model haiku

# Send commands to different LLMs in Parallel
fast-agent --model kimi,gpt-5-mini.low

# Specifying servers from configuration
fast-agent go --servers=fetch,filesystem --model=haiku

# Directly connecting to HTTP/SSE servers via URLs
fast-agent go --url=http://localhost:8001/mcp,http://api.example.com/sse

# Connecting to an authenticated API endpoint
fast-agent go --url=https://api.example.com/mcp --auth=YOUR_API_TOKEN

# Run an NPX package directly
fast-agent --npx @modelcontextprotocol/server-everything 

# Non-interactive mode with a single message
fast-agent go --message="What is the weather today?" --model=haiku

# Using a prompt file
fast-agent go --prompt-file=my-prompt.txt --model=haiku

# Specify a system prompt file
fast-agent go -i my_system_prompt.md

# Specify a skills directory
fast-agent --skills ~/my-skills/

# Provider LLM shell access (use at your own risk)
fast-agent -x

URL Connection Details

The --url parameter allows you to connect directly to HTTP or SSE servers using URLs.

  • URLs must have http or https scheme
  • The transport type is determined by the URL path:
  • URLs ending with /sse are treated as SSE transport
  • URLs ending with /mcp or automatically appended with /mcp are treated as HTTP transport
  • Server names are generated automatically based on the hostname, port, and path
  • The URL-based servers are added to the agent's configuration and enabled

Authentication

The --auth parameter provides authentication for URL-based servers:

  • When provided, it creates an Authorization: Bearer TOKEN header for all URL-based servers
  • This is commonly used with API endpoints that require authentication
  • Example: fast-agent go --url=https://api.example.com/mcp --auth=12345abcde