chatchain

name	chatchain
description	Send questions to other LLM models — GPT-4o, GPT-4, o1, o3, Gemini, Claude (via API), etc. Use this skill whenever the user wants to ask, query, chat with, or get answers from another AI model, including: "ask GPT...", "let Gemini explain...", "what does Claude think about...", "compare answers from different models", "get a second opinion from another LLM", or any request that involves calling OpenAI, Anthropic, Gemini, or Vertex AI models.
allowed-tools	["Bash(chatchain *)"]

ChatChain CLI — Agent Skill

ChatChain is a CLI tool for chatting with multiple LLM providers.

Prerequisites

First check if ChatChain is installed:

command -v chatchain

If not installed, install via Homebrew:

brew tap joyqi/tap && brew install chatchain

Or via Go:

go install github.com/joyqi/chatchain@latest

CRITICAL: Discover Providers and Models Before Calling

DO NOT guess or hardcode provider names or model names. Always discover them first using chatchain -l.

Step 1: List available providers

chatchain -l

This shows all built-in providers and any custom aliases configured in ~/.chatchain.yaml. Only use providers that appear in this list.

Step 2: List available models for the chosen provider

chatchain -l <provider>

This queries the provider's API and returns the actual available models. Only use model names that appear in this list. If the user asks for a specific model (e.g. "ask GPT-4o"), find the closest match from the list.

Step 3: Send the message

chatchain <provider> -M <model> -m "<message>"

Key Flags

Flag	Description
-l, --list	List configured providers (no arg), or models for a provider (with arg)
-M, --model <model>	Specify model — must be a real model from chatchain -l <provider>
-m, --message <msg>	Non-interactive mode: send a single message and exit (use - to read from stdin)
-s, --system <prompt>	Set system prompt
-t, --temperature <val>	Set temperature (0.0–2.0)
-k, --key <key>	API key (overrides env var)
-u, --url <url>	Custom API base URL
-c, --config <path>	Path to config file (default: ~/.chatchain.yaml)
-v, --verbose	Show raw API responses

Providers and Environment Variables

Provider	Subcommand	Env Var	Notes
OpenAI	openai	OPENAI_API_KEY	GPT models
Anthropic	anthropic	ANTHROPIC_API_KEY	Claude models
Gemini	gemini	GOOGLE_API_KEY	Gemini models
Vertex AI	vertexai	—	Uses Google Cloud ADC
OpenAI Responses	openresponses	OPENAI_API_KEY	OpenAI Responses API

Custom aliases may also be configured in ~/.chatchain.yaml (e.g. deepseek, chatgpt). Always run chatchain -l to see the full list.

Config File

ChatChain supports a YAML config file (~/.chatchain.yaml) for persistent API keys, default models, and custom provider aliases. Priority: CLI flag > env var > config file.

providers:
  deepseek:
    type: openai
    key: sk-deepseek-xxx
    url: https://api.deepseek.com/v1
    model: deepseek-chat
    system: "You are a helpful coding assistant"

With a config like this, chatchain deepseek -m "hello" works as a provider alias.

Usage Examples

Full workflow (recommended)

# 1. Discover providers
chatchain -l

# 2. Pick a provider, discover its models
chatchain -l openai

# 3. Send the message with a real model name
chatchain openai -M gpt-4o -m "What is the capital of France?"

With system prompt

chatchain anthropic -M claude-sonnet-4-20250514 -s "You are a helpful coding assistant" -m "Explain async/await in JavaScript"

Pipe content via stdin

echo "Summarize this text" | chatchain gemini -M gemini-2.0-flash -m -

Note: -m - (dash) reads the message from stdin.

With temperature

chatchain openai -M gpt-4o -t 0.7 -m "Write a haiku about programming"

Important Notes

• NEVER guess provider or model names — always run chatchain -l and chatchain -l <provider> first
• Always use -m for non-interactive mode (otherwise it opens an interactive TUI)
• Use -m - to read the message from stdin
• If no -M is specified, ChatChain will prompt for model selection interactively (avoid this in automation)
• API keys are read from environment variables by default; use -k only if the env var is not set