Command line

anchor setup
anchor [--model <name>] [--yolo] [--allow <rule>]... [--resume [id]] [-p [prompt]] [--until <check>]
       [--max-rounds <n>] [--timeout <seconds>] [--json] [--plain] [--theme <name>]

With no options, anchor starts an interactive session in the current directory. anchor setup runs the setup wizard and exits.

Options

Option	Description
-m, --model <name>	The model to use. Overrides provider.model in the config.
--yolo	Don’t ask before writes, commands and reads outside the directory. Hard denials still apply. More
--allow <rule>	Don’t ask for this, for this run only. Repeatable. <rule> is a program (dotnet), an MCP tool (mcp__server__tool), or edits for file writes in the directory. Hard denials still apply. More
-r, --resume [id]	Continue the latest session in this directory, or the session with this id or id prefix.
-p, --print [prompt]	Run one prompt and print the answer. Piped stdin is added to the prompt. Without --yolo, anything that would ask is refused.
--until <check>	With -p: after each turn run <check>, and keep working until it exits 0. More
--max-rounds <n>	With -p: stop after n model requests (exit code 5).
--timeout <seconds>	With -p: stop after this many seconds (exit code 124).
--json	Write events as JSON lines. Without -p, also read requests from stdin. More
--plain	Use the line-by-line REPL instead of the full-screen one. It’s also used when stdin or stdout isn’t a terminal.
--theme <name>	Use a color theme for this run: default, bright, light or mono. Overrides theme in the config.
--version	Print the version.
-h, --help	Print usage.

--model, --resume and -p never take a value that starts with -. So in anchor --resume -p "hi", --resume continues the latest session and "hi" is the prompt.

Examples

anchor setup                                  # choose a provider and model
anchor                                        # interactive
anchor -m claude-opus-5-5                     # interactive, with another model
anchor --resume                               # continue the latest session here
anchor -p "why does the build fail?"          # one answer, then exit
git diff | anchor -p "review this change"     # piped input
anchor -p --yolo "fix it" --until "make test" # work until the tests pass
anchor -p --allow edits --allow make "fix it" --until "make test" --max-rounds 40 --timeout 900
anchor -p "list the TODOs" --json             # JSON events
anchor --json                                 # editor protocol

Environment variables

Variable	Description
ANTHROPIC_API_KEY	Key for Claude models. When set, the default model is claude-sonnet-5.
XAI_API_KEY	Key for Grok models. When set (and no Anthropic key), the default model is grok-4.5.
OPENAI_API_KEY	Key for OpenAI models.
ANCHOR_HOME	Where config and sessions live, instead of ~/.anchor.
NO_COLOR	Turn off colored output.
ANCHOR_DEBUG	Set to 1 to also print a bug’s stack trace on the terminal.

A model on another OpenAI-compatible server reads its key from the variable named in provider.apiKeyEnv. When a key variable is unset, anchor uses the key anchor setup saved for it in the OS keychain, or in ~/.anchor/credentials where there’s no keychain. MCP server configs can reference any variable as ${NAME}.

Crash logs

When anchor hits a bug, it says so in one line and writes the details, including the stack trace, to a file in ~/.anchor/logs/, such as crash-20261009-221503-3fa9c1.log. Only you can read it, and the newest 10 are kept. Please attach it if you report the problem. Failures that aren’t bugs, such as a rejected key or a provider that’s down, are only reported, not recorded.

Exit codes

Code	Meaning
0	Completed (and the --until check passed, if set).
1	Error.
2	Usage error.
3	Stopped by the loop guard.
4	The --until check never passed.
5	Reached the --max-rounds limit.
124	Reached the --timeout limit.
130	Cancelled.