Tally: a household ledger you talk to, on Alexa+ and MCP

A shared household ledger you talk to. Say “I paid $60 for groceries, split with Chris and Maya” and Tally records it, keeps the balances and answers “who owes whom”. Built as an MCP server, so Alexa+ or any agent can use it; submitted to the Amazon Developer hackathon (Alexa+ track).

Try it (voice and text playground): tally-playground.onrender.com · Code: github.com/bisale24-ops/tally-mcp · Demo: youtu.be/KwRA_jD7kJs

The model only picks a tool. Splits, settle-ups and undo are deterministic code on the server, so a retried request never records an expense twice.

Two routes to the same tool call. Spoken amounts and names go through the model, with a pattern parser as fallback, so the ledger keeps working when the model is slow.

265 tests in 8 layers, from the money arithmetic to a full MCP session.

A friction log documents every place the platform got in the way, with a reproduction for each.