Crumb

Deployment observability for Kamal-deployed Rails apps. Crumb records every deploy — who shipped what commits, which files changed, success/failure, rollbacks — and lets you query that history (including from an AI assistant) instead of spelunking through git logs and CI dashboards.

The repo ships two independent gems:

Gem	Path	Who installs it	What it is
crumb	engine/	The deployed app	A mountable Rails engine: stores deploy records and exposes a small write/read API. Kamal hooks feed it on each deploy.
crumb-mcp	mcp/	Each developer, locally	A standalone MCP server that queries one or more app endpoints, so an AI assistant can answer "what deployed to staging today?"

How it fits together

kamal deploy ──► .kamal/hooks/pre-deploy ──┐
                 .kamal/hooks/post-deploy ──┤ POST/PATCH (ingest secret)
                                            ▼
                            crumb engine  (mounted at /crumb in the app)
                                            ▲
                                            │ GET (read token)
crumb-mcp ◄── Claude Code / MCP client ─────┘

• The engine owns the data and the HTTP API. Writes are authenticated with a shared ingest secret; reads with per-developer access tokens.
• The MCP server is a thin client over the read API, fanning out across the endpoints you configure locally.

Getting started

1. Install the engine in your app — see engine/README.md.
2. Install the MCP server locally — see mcp/README.md.

License

Available as open source under the terms of the MIT License.