Founders shouldn't spend their evenings on invoicing busywork. Billr is open-source invoicing with an MCP server built in: connect Claude Code, Codex, Cursor or any MCP client over OAuth and your agent can log time, track expenses, draft estimates and send invoices through 53 tools, with bookkeeper-level permissions. Every agent action is badged in one dashboard. Hosted at billr.cc for $19/month (14-day free trial, no platform fee), or self-host free under Apache-2.0. GitHub: https://github.com/ethanplusai/billr
Running a small studio, I kept asking my coding agent to do everything except the billing. Invoicing was the last manual chore, so I built an invoicing app my agent could operate safely, with permissions and a clear audit trail of every action.