Diffler
Prove you understand the diff.
Diffler generates comprehension quizzes from Git branch diffs for Claude Code,
OpenCode, and pull-request workflows. Its first milestone is an agent skill that
collects focused branch context, generates graded questions, and publishes them
to Google Forms.
Status
Diffler is in early development. The repository contains the TypeScript project
foundation, versioned quiz-document contract, local branch-context collection,
Google Forms authentication and publication, and a portable Claude Code and
OpenCode skill.
Requirements
- Node.js 24 or newer
- pnpm 10.33.4
- Git 2.42 or newer
Development
Install dependencies and run all checks:
pnpm install --frozen-lockfile
pnpm check
pnpm build
Run the development CLI:
pnpm start -- --help
pnpm start -- context --base main
pnpm start -- publish .diffler/quiz.json --context .diffler/context.json
To authorize Google Forms publication, follow the
Google authentication setup, then run
diffler auth login. Maintainers can still select a bring-your-own Desktop
client with --credentials <path>.
See Google Forms publishing for the publication
flow and manual verification steps.
Install the agent workflow using the skill installation guide.
Maintainers can inspect and install the exact npm tarball by following the
npm publication guide.
The aggregate check command verifies formatting, linting, types, and tests.
CI runs the same checks on pull requests and pushes to main.
The stable Review Gate check and recommended branch protection are documented
in Repository Settings.
Maintainers can verify both canonical Google Cloud environments without making
changes by running pnpm cloud:check; see
Google Authentication.
Intended Workflow
- Compare the current branch with its merge base.
- Exclude generated and low-value changes.
- Ask questions about behavior, rationale, risks, and changed invariants.
- Validate the quiz document.
- Create and publish an automatically graded Google Form.
Repository Layout
src/ TypeScript CLI and domain implementation
docs/ Context and quiz contracts
skills/diffler/ Claude Code and OpenCode skill (planned)
.github/workflows/ Continuous integration
Design Principles
- Prefer a small, verifiable implementation over speculative flexibility.
- Keep Git, quiz-domain, and Google API responsibilities separate.
- Treat diffs, generated questions, credentials, and OAuth tokens as sensitive.
- Make local commands and CI enforce the same checks.
License
MIT. See LICENSE.
@jamestkelly