Usage

From inside the repo, on the branch you want to review:

saga

From inside the repo, reviewing a different branch:

saga --base main --head my-feature -o saga.html --open

Run it from anywhere with --repo:

saga --repo ~/src/some-project --base main --head my-feature -o out.html

From a GitHub PR URL

Point saga straight at a pull request by passing its URL as the first argument. No checkout is needed and it works from any directory:

saga https://github.com/owner/repo/pull/5
saga https://github.com/owner/repo/pull/5 --model openai/gpt-4o -o pr5.html

This fetches the PR’s diff, commits, and branch names with the gh CLI (so gh must be installed and authenticated), then builds the saga exactly as it would for a local branch. In this mode the PR defines the change set, so --base, --head, and --repo are ignored.

Flags

All flags are documented in saga --help, the following flags apply to local and GitHub usage.

Flag	Default	Meaning
--base	auto-detected	Base ref to diff against (defaults to the repo’s default branch, e.g. origin/main); local mode only
--head	current branch	Head ref to walk through; local mode only
--intent PATH	—	Optional plan/spec describing the change’s intent, for plan-aware narration and deviation flagging
--model	anthropic/claude-opus-4-8	provider/model string (see Providers); also $SAGA_MODEL
-o, --output	saga.html	Output file
--repo	cwd	A path inside the target git repo; local mode only
--open / --no-open	on	Open the result in a browser (the served URL when serving, else the file:// page)
--serve / --no-serve	on	On an interactive terminal, serve the saga after generating so comments save into the file (see Reviewing); --no-serve writes and exits

As a Claude Code skill

The skills/ directory contains a Claude Code skill. To install it:

cp -R "$(pwd)/skills" ~/.claude/skills/saga

• saga — say “/saga” (or “give me a walkthrough of this branch”) to generate a saga. It resolves the base/head refs and runs the tool for you.