MCP server · Analytics

Tallybook MCP server

Lets your AI check what its own sessions cost and what would have been cheaper.

Analytics For it and development Monitoring

Tallybook is a small tool that reads the Claude Code and Codex sessions saved on your computer and works out what each one cost. It runs entirely on your machine, with no proxy and no API key, and nothing is sent anywhere. It is handy if you use Claude Code or Codex often and want to know where your money is going.

What is an MCP server? The 30-second version

On its own, your AI can only chat with you. An MCP server is a small helper program that gives your AI one extra skill or a connection to something else. Here, that helper is tallybook-mcp, and it connects your AI to the cost records of your own Claude Code and Codex sessions on your disk. Once it is added, you can just ask your AI what it has been spending, and it will look it up for you.

What this MCP server does

You ask your AI something like what did I spend this week, or which session cost the most. Your AI passes that question to the tallybook-mcp helper. The helper reads the session files already stored on your computer and prices them. It then hands the numbers, the comparisons and any suggested fixes back to your AI, which explains them to you in the chat.

Flow diagram: you ask your AI “What did my AI sessions cost this week?”, on your own computer the Tallybook MCP server works with your session files, and you get back costs and simple advice.

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What you can do with it

See what each Claude Code or Codex session cost
Compare this week's spend against last week's
Break spending down by sub-agent and by model
Rank your sessions by how much they cost
Get plain English findings on what would have been cheaper
Read a suggested patch for a finding
Check whether a past model swap actually saved money

Try asking your AI

“What did my Claude Code sessions cost this week?”
“Which session cost me the most in the last 7 days?”
“Compare this week's spend with last week's.”
“Show me the biggest finding and what I should change.”

What it gives back to you

You get back answers in plain words: totals, per-session costs, week-on-week comparisons and cache hit rates. Findings come as short explanations of what happened, why, and what to change, and you can ask for the sessions behind a finding as evidence. A finding can also come with a suggested patch shown as a diff you could apply. Everything appears right in the chat, and you can also open the same report in your browser.

Before you start

What you need

Claude Code or Codex installed and used on this machine, so there are sessions to price
The tallybook tool installed (it comes with the tallybook-mcp helper)

Good to know

It reads the Claude Code and Codex session files on your disk, so it can see the contents of those sessions, though nothing leaves your machine.

Install it with your AI

Add Tallybook MCP server to your AI, no technical skills needed

You don't install anything by hand. You copy one prompt, paste it into an AI that can work on your computer, and it checks, installs and connects the server for you, asking you when it needs something.

Sign in to get the install prompt

Members get a ready-made prompt that lets the Claude desktop app check Tallybook MCP server, install it and connect it for them, step by step. You don't need any technical skills: you copy, paste and answer a few questions. Your connected AI can also find and install any of the 4,066 MCP servers here for you.