Cryyer

Automated product update emails, with per-product voice powered by LLM-drafted content. Supports multiple audiences per product, multiple LLM providers (Anthropic, OpenAI, Gemini), and multiple email providers (Resend, Gmail).

Website: cryyer.dev GitHub: atriumn/cryyer Issues: Report a bug

Cryyer supports two pipelines:

Release pipeline (manual approval before send):

1. Push to main → release-please opens a version-bump PR
2. draft-email.yml generates a draft file (drafts/vX.Y.Z.md) and commits it to the PR branch
3. Merge the PR → tag pushed → release.yml publishes to npm → GitHub Release created
4. send-email.yml fires on release publish but pauses for approval — review the draft, then approve to send

Weekly pipeline (manual review via GitHub issues):

1. weekly-draft.yml runs on cron (Monday 1pm UTC) — gathers GitHub activity, generates LLM drafts, creates GitHub issues for human review
2. send-update.yml fires when a draft issue is closed — sends emails to subscribers

Quickstart

For humans — interactive wizard

mkdir my-updates && cd my-updates
npx @atriumn/cryyer init

The interactive setup walks you through product name, GitHub repo, voice/tone, LLM provider, subscriber store, and API keys — then creates everything you need:

• products/*.yaml — product configuration
• .env — API keys and settings
• subscribers.json — subscriber list (when using JSON store)
• .gitignore — ignores .env and data files

For CI — flags + env vars

npx @atriumn/cryyer init --yes \
  --product "My App" \
  --repo owner/my-app \
  --voice "Friendly and concise" \
  --pipeline weekly

Non-interactive mode (--yes or CI=true) skips all prompts. Secrets are read from environment variables (ANTHROPIC_API_KEY, RESEND_API_KEY, etc.) instead of being written to .env. Defaults: anthropic LLM, json subscriber store, resend email, no workflows.

Available flags: --product, --repo, --voice, --llm, --subscriber-store, --email-provider, --from-email, --pipeline (weekly, release, or both).

For agents — write files directly

AI coding agents (Claude Code, Cursor, etc.) can skip init entirely and write the files themselves. All you need is a products/*.yaml file — see Product Configuration for the schema.

Then:

npx @atriumn/cryyer check         # validate your setup
npx @atriumn/cryyer run --dry-run  # preview a draft email

When you're ready to run for real:

npx @atriumn/cryyer run          # full pipeline: gather → draft → send

Or run the two stages separately:

npx @atriumn/cryyer draft        # generate drafts → create GitHub issues
npx @atriumn/cryyer send         # send emails when a draft issue is closed

For release-triggered emails, use the file-based commands:

npx @atriumn/cryyer draft-file --product my-app --version 1.2.0  # generate a draft file
npx @atriumn/cryyer send-file drafts/v1.2.0.md --product my-app  # send from draft file

You can also create products/*.yaml files manually — see Product Configuration for all fields, and .env.example for all environment variables.

Subscriber Stores

Set SUBSCRIBER_STORE to choose your backend. Default is supabase.

JSON File (simplest)

SUBSCRIBER_STORE=json

Variable	Default	Description
SUBSCRIBERS_JSON_PATH	./subscribers.json	Path to subscriber data
EMAIL_LOG_JSON_PATH	./email-log.json	Path to email send log

File format — array of objects with email, optional name, and productIds:

[
  { "email": "alice@example.com", "name": "Alice", "productIds": ["my-app", "other-app"] }
]

Public repos: Don't use the JSON store if your repo is public — subscribers.json would need to be committed, exposing subscriber emails. Use the GitHub Gist store instead.

GitHub Gist

Stores subscribers in a private GitHub Gist — same JSON format as the JSON file store, but private. Ideal for public repos.

SUBSCRIBER_STORE=gist

Variable	Description
GITHUB_GIST_ID	ID of a private Gist containing subscribers.json
GITHUB_TOKEN	Classic PAT with gist scope (fine-grained PATs do not support gists; the default Actions token cannot access private gists)

Setup:

1. Create a secret Gist with a file named subscribers.json containing []
2. Copy the Gist ID from the URL
3. Create a classic PAT with gist scope (fine-grained PATs don't work with gists)
4. Add both as repo secrets (SUBSCRIBERS_GIST_ID, SUBSCRIBERS_GIST_TOKEN)

Same file format as the JSON store:

[
  { "email": "alice@example.com", "name": "Alice", "productIds": ["my-app"] }
]

When using audiences, use compound keys in productIds (e.g. "my-app:beta").

Supabase (default)

SUBSCRIBER_STORE=supabase  # or just don't set it

Variable	Description
SUPABASE_URL	Your Supabase project URL (https://[project-id].supabase.co)
SUPABASE_SERVICE_KEY	Supabase service role key

Expects a beta_testers table with columns: email, name, product, unsubscribed_at.

Google Sheets

SUBSCRIBER_STORE=google-sheets

Variable	Description
GOOGLE_SHEETS_SPREADSHEET_ID	The ID from your spreadsheet URL
GOOGLE_SERVICE_ACCOUNT_EMAIL	Service account email
GOOGLE_PRIVATE_KEY	Service account private key (PEM format)

Cryyer looks for a sheet tab named after the product ID (e.g. my-app), falling back to the first sheet. Expected columns: email, name (optional), unsubscribed (optional, set to true to exclude).

Email send logging is a no-op with this backend (read-only).

Google Sheets setup walkthrough

1. Enable the Google Sheets API

• Go to console.cloud.google.com (create a project if you don't have one)
• Navigate to APIs & Services > Library
• Search for "Google Sheets API" and click Enable

2. Create a service account

• Go to APIs & Services > Credentials
• Click Create Credentials > Service account
• Name it (e.g. cryyer-sheets-reader) and click Done

3. Generate a key

• Click the service account you just created
• Go to the Keys tab
• Click Add Key > Create new key > JSON
• Save the downloaded file

4. Set your environment variables

From the downloaded JSON file, grab client_email and private_key:

GOOGLE_SERVICE_ACCOUNT_EMAIL=cryyer-sheets-reader@your-project.iam.gserviceaccount.com
GOOGLE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\nMIIE...\n-----END PRIVATE KEY-----\n"

5. Get the spreadsheet ID

From the spreadsheet URL:

https://docs.google.com/spreadsheets/d/SPREADSHEET_ID_HERE/edit
                                       ^^^^^^^^^^^^^^^^^^^^

GOOGLE_SHEETS_SPREADSHEET_ID=1BxiMVs0XRA5nFMdKvBdBZjgmUUqptlbs74OgVE2upms

6. Share the spreadsheet

Share the spreadsheet with your service account email (from step 4) as an Editor (required for add/remove subscriber support; Viewer is sufficient for read-only use).

7. Set up columns

Row 1 should have these headers:

email	name	unsubscribed
alice@example.com	Alice
bob@example.com	Bob
charlie@example.com		true

Name the sheet tab after your product ID (e.g. my-app), or just use the default first sheet if you have one product.

LLM Providers

Set LLM_PROVIDER to choose your LLM backend. Default is anthropic.

Variable	Default	Description
LLM_PROVIDER	anthropic	anthropic, openai, or gemini
LLM_MODEL	Per-provider default	Override the default model
ANTHROPIC_API_KEY	—	Required when LLM_PROVIDER=anthropic
OPENAI_API_KEY	—	Required when LLM_PROVIDER=openai
GEMINI_API_KEY	—	Required when LLM_PROVIDER=gemini

Default models: Anthropic claude-sonnet-4-5-20250514, OpenAI gpt-4o, Gemini gemini-1.5-flash.

Product Configuration

Products are defined as YAML files in products/. Each file represents one product.

Field	Required	Description
id	Yes	Unique identifier, also used as GitHub issue label
name	Yes	Display name
voice	Yes*	LLM voice/tone instructions (injected into the draft prompt)
repo	Yes	owner/repo for GitHub activity gathering
emailSubjectTemplate	Yes*	Subject line template — use {{weekOf}} for the date or {{version}} for the release version
audiences	No	List of audience-specific overrides (see docs site)
tagline	No	Product tagline
from_name	No	Override sender name for this product
from_email	No	Override sender email for this product
reply_to	No	Reply-to address

* Required when audiences is not set. When using audiences, voice and emailSubjectTemplate are set per-audience instead.

GitHub Actions Workflows

weekly-draft.yml

Runs every Monday at 1pm UTC. Gathers GitHub activity and creates draft issues.

Secrets needed: GITHUB_TOKEN, CRYYER_REPO, and the API key for your chosen LLM_PROVIDER.

send-update.yml

Fires when an issue with the draft label is closed. Sends emails to subscribers.

Secrets needed: GITHUB_TOKEN, email provider credentials (RESEND_API_KEY or GMAIL_REFRESH_TOKEN), FROM_EMAIL, plus the secrets for your chosen SUBSCRIBER_STORE.

draft-email.yml

Runs when a release-please--* PR is opened or synced. Generates drafts/vX.Y.Z.md via LLM and commits it to the PR branch.

release.yml

Runs on v* tag push (after release-please PR is merged). Typechecks, tests, publishes to npm, creates GitHub Release.

send-email.yml

Runs when a GitHub Release is published. Reads the draft file and sends emails to subscribers. Pauses for manual approval via a production environment with required reviewers.

ci.yml

Runs on push/PR to main. Lints, typechecks, and runs tests.

Composite Actions

Reusable composite actions for consumer repos: atriumn/cryyer/.github/actions/draft-file@v0 and atriumn/cryyer/.github/actions/send-file@v0. Run cryyer init to scaffold wrapper workflows. See the docs site for full input references.

MCP Server

Cryyer includes an MCP server that lets you review, edit, and send drafts conversationally from any MCP client. It also supports subscriber management.

The MCP server uses stdio transport and is available as a separate binary: cryyer-mcp.

Standalone usage

npx @atriumn/cryyer-mcp

Or if installed locally:

pnpm run build   # compiles dist/mcp.js
node dist/mcp.js

Claude Desktop

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "cryyer": {
      "command": "npx",
      "args": ["@atriumn/cryyer-mcp"],
      "env": {
        "GITHUB_TOKEN": "ghp_...",
        "CRYYER_REPO": "owner/repo",
        "CRYYER_ROOT": "/path/to/cryyer",
        "RESEND_API_KEY": "re_...",
        "FROM_EMAIL": "updates@example.com",
        "SUBSCRIBER_STORE": "json",
        "LLM_PROVIDER": "anthropic",
        "ANTHROPIC_API_KEY": "sk-ant-..."
      }
    }
  }
}

Other MCP clients (Cline, Continue, Windsurf, etc.)

Any MCP client that supports stdio transport can use Cryyer. The generic config is:

• Command: npx @atriumn/cryyer-mcp (or node /path/to/cryyer/dist/mcp.js)
• Transport: stdio
• Environment variables: same as above

Only GITHUB_TOKEN and CRYYER_REPO are needed for read-only tools (list_drafts, get_draft). Other env vars are needed for sending, regenerating, and subscriber management.

Debugging

Test the server interactively with the MCP Inspector:

npx @modelcontextprotocol/inspector node dist/mcp.js

All log output goes to stderr (stdout is reserved for JSON-RPC). If something isn't working, check stderr for error messages.

Tools

Tool	Description
list_drafts	List open draft issues
get_draft	Get full draft content with subscriber count
update_draft	Save revised subject + body
send_draft	Send emails, close issue, post stats
regenerate_draft	Re-gather activity + re-draft via LLM
list_products	Show configured products
list_subscribers	Show subscribers for a product
add_subscriber	Add a subscriber to a product
remove_subscriber	Unsubscribe someone from a product

Prompt

Use the review_drafts prompt for the Monday morning review workflow — it walks through each pending draft and asks whether to send, edit, regenerate, or skip.

Badge

Show that your project uses Cryyer for emails:

[![Emails by Cryyer](https://img.shields.io/badge/emails%20by-cryyer-2c3e6b?style=flat&logo=data%3Aimage%2Fpng%3Bbase64%2CiVBORw0KGgoAAAANSUhEUgAAABIAAAASCAYAAABWzo5XAAABEElEQVR42r2UIU4EQRREq2bWrSIIAgmCYJCbgMESNIYDLHfgEnAJFAdAYUCgOAUCgYWsJGRnH4KaMDuZzO6GLN%2F83%2Bn%2B1b%2Bq0i39RwAlUPwVpGgBOrWXBagbhsA1cNjcKwuvBFYmP%2FITt8BBc9KlwIBB8jm%2FsQ%2BMgQdgGyh6wQDn0A5wF5AbYBeYZD2y53XsFLksJOA%2BTRXwCrxlfdmkv0joTeADmAKzBr2X%2BrI2rfZo9S2nkjZSW9I09XMNYJs%2BoHrzS9J76pmkgaQrSeMAs4r1F6HzmXzWdLQdXao75PckVaFVSTrps7vTvsw9imbD5KPo0knLXc7ZBjiWtJVGS5rYflr7T%2BEFr9%2Fz4rla%2B0TfpaQEQwE4wDoAAAAASUVORK5CYII%3D)](https://github.com/atriumn/cryyer)

Development

pnpm install         # install dependencies
pnpm run build       # compile TypeScript
pnpm run init        # interactive product setup + .env scaffolding
pnpm run check       # validate config, tokens, and connections
pnpm run typecheck   # type-check without emitting
pnpm run lint        # ESLint
pnpm test            # run tests (vitest)
pnpm run test:watch  # run tests in watch mode
pnpm run dev         # build + run
pnpm run mcp         # run MCP server