cog

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A small terminal coding agent. Zero external dependencies (just the Python 3.9+ standard library) and ships as a single file you can drop anywhere there's a Python interpreter.

Talks to the Anthropic Messages API, or anything else that speaks it: Minimax, Kimi, GLM (Z.ai), OpenRouter, Ollama, LM Studio, and so on.

Install

cog is a single Python file with a shebang. Drop it on your $PATH:

curl -fsSL https://raw.githubusercontent.com/6/cog/main/cog.py -o ~/.local/bin/cog && chmod +x ~/.local/bin/cog

Make sure ~/.local/bin is on your $PATH. Then cog is available globally.

Usage

cog

Requires ANTHROPIC_API_KEY set in your environment (or a different env var via api_key_env in config).

Flags: --auto to skip tool approval prompts, --cwd PATH to set working directory, --verbose for full API JSON.

Config

Optional. Create ~/.config/cog/config.json (respects XDG_CONFIG_HOME):

{
  "model": "claude-sonnet-4-6",
  "api_base_url": "https://api.anthropic.com",
  "api_key_env": "ANTHROPIC_API_KEY",
  "auto_approve": false,
  "max_tool_calls_per_turn": 10,
  "shell_timeout_seconds": 30,
  "tool_output_max_bytes": 32768,
  "skills_dirs": [],
  "mcp_servers": [
    {
      "name": "local",
      "url": "http://127.0.0.1:8001/mcp",
      "headers": {"Authorization": "Bearer ${MCP_TOKEN}"}
    }
  ]
}

All fields are optional and fall back to defaults. ${ENV_VAR} syntax is expanded in string values. Logs go to ~/.config/cog/logs/ and OAuth tokens to ~/.config/cog/tokens/.

Other providers

cog speaks the Anthropic Messages API, so anything else that speaks it works too. Point api_base_url at the provider's endpoint, set model to whatever they call the model, and api_key_env to the env var holding your key. For example, to use Kimi:

{
  "api_base_url": "https://api.moonshot.ai/anthropic",
  "model": "kimi-k2.6",
  "api_key_env": "MOONSHOT_API_KEY"
}

A few that work today (model names move fast, check the provider's docs for the current flagship):

Provider	api_base_url	Example model
Minimax	https://api.minimax.io/anthropic	MiniMax-M2.7
Kimi (Moonshot)	https://api.moonshot.ai/anthropic	kimi-k2.6
GLM (Z.ai)	https://api.z.ai/api/anthropic	glm-5.1
LM Studio (local)	http://localhost:1234	whatever you loaded
Ollama (local)	http://localhost:11434	whatever you pulled

For local endpoints with auth disabled you can omit api_key_env.

Tools

• read_file / write_file / str_replace -- file operations
• list_dir -- directory listing
• run_shell -- shell commands
• MCP tools -- discovered from configured MCP servers

Keyboard shortcuts

Shortcut	Action
Enter	Submit
Opt+Enter	Newline
Opt+Left/Right	Word jump
Opt+Delete	Delete word
Cmd+Delete	Delete line
Ctrl+A / Ctrl+E	Home / End
Ctrl+C	Exit

Local development

cog itself has no runtime dependencies, so python3 cog.py is all you need to run it. Dev tasks are wired up through mise:

mise install       # installs the pinned dev tools (ruff, basedpyright)
mise run test      # runs the unittest suite under tests/
mise run lint      # ruff check (with E701/E702 ignored, terse one-liners are intentional)
mise run typecheck # basedpyright

For scripts and CI, cog falls back to a line-oriented mode when stdin is not a TTY:

echo "list files in docs" | python3 cog.py --auto

In this mode slash commands are ignored, approval prompts are answered from the next stdin line, and output is plain text with no ANSI.