Nuntia — AI release notes & migration guides for GitHub

Nuntia is a GitHub Action that writes release notes and migration guides from a commit range: it gathers commit messages, follows the issues, pull requests, and commits they reference, and feeds the full context to Gemini with a prompt you control. It runs on demand in your workflow with your own API key — no service to host.

The default prompt produces a themed changelog rather than a per-commit log: a highlights section, an upgrading section with breaking changes and before/after diffs, and net changes grouped by feature area with trailing reference links. The prompt is fetched from a URL, so you can swap in your own format without forking the action.

Quick start

1. Add a GEMINI_API_KEY secret to your repository or organization (get a key).
2. Add a manually-triggered workflow, like the ready-to-use examples/workflows/nuntia.yml:

name: Nuntia (Release Notes)

on:
  workflow_dispatch:
    inputs:
      base-commit:
        description: "Start commit SHA"
        required: true
      head-commit:
        description: "End commit SHA"
        required: true

jobs:
  release-notes:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      issues: read
      pull-requests: read
    steps:
      - uses: actions/checkout@v7

      - uses: danielchalmers/Nuntia@main
        with:
          base-commit: ${{ inputs.base-commit }}
          head-commit: ${{ inputs.head-commit }}
          branch: main
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          GEMINI_API_KEY: ${{ secrets.GEMINI_API_KEY }}

      - uses: actions/upload-artifact@v7
        with:
          name: nuntia-release-notes-${{ github.run_number }}
          path: artifacts
          if-no-files-found: error

3. Run it from the Actions tab with the first and last commit of the release, then download the release notes from the run's artifacts.
4. Optionally write your own prompt — start from the example prompt, host it anywhere with a raw URL (a Gist works well), and point prompt-url at it.

How it works

• Resolves the inclusive commit range from the base commit, head commit, and branch.
• Scrapes commit messages and follows linked issues, PRs, and commits, with configurable depth and caps.
• Sends the aggregated context to Gemini using the prompt fetched from prompt-url.
• Writes the release notes markdown (plus payload/context debug files) to the artifacts/ directory for your workflow to upload.

Inputs

Input	Purpose	Default
base-commit	Start commit SHA (inclusive).	Required
head-commit	End commit SHA (inclusive).	Required
branch	Branch name (branch or owner/repo@branch).	Required
prompt-url	URL to raw prompt template content.	example prompt
model	Gemini model identifier.	gemini-3.5-flash
max-linked-items	Maximum linked issues/PRs/commits to fetch.	5
max-reference-depth	Depth to follow references inside linked descriptions.	2
max-item-length	Maximum length for each commit message and linked item title/body field.	5000

Outputs

Output	Purpose
release-notes-path	Filesystem path to the release notes markdown.
input-tokens	Gemini prompt token count.
output-tokens	Gemini output token count.