Let your AI agent calculate with your Excel model.
WorkbookAPI checks your Excel model in the browser for free, with a hosted calculation API for your AI agent. A plausible estimate is not the same as a calculated result.
Check your workbook — free, it never leaves your browser
The assistant needs the model's math.
An analyst may ask an assistant for a payback period, quote, or forecast. An agent developer needs a calculation tool. Pasting the workbook into a prompt does not check the answer against its formulas.
Why the usual options hurt
Asking an assistant to rewrite formulas creates a second model to maintain. Running Excel on a server adds maintenance. Asking an analyst to calculate each answer by hand limits the assistant's usefulness.
How it works with WorkbookAPI
Drop the model into the free browser check. See which formulas compute exactly like Excel before connecting any agent.
Recalculate and save in Excel first. The check compares against saved results for the current inputs. A match does not prove every possible agent request will be correct.
The hosted API and bulk scenarios are live. After the browser check, upload your workbook separately to the server. Start free trial or read the API docs. Shareable and embeddable web forms stay on the home-page waitlist.
Your agent sends explicit inputs and uses the returned model outputs in its answer. The analyst keeps the model in Excel. Upload a new workbook version to update the calculation the agent calls.
Illustration: an assistant answering a payback question
The assistant would ask the model to calculate simple payback using stated assumptions.
- Inputs: $20,000 setup cost, $5,000 annual savings, and no recurring costs.
- Outputs: A four-year simple payback period.
This illustrates a tool call you can build with the hosted API. Correct units and assumptions still matter.
What is not supported
Macros/VBA, Power Query, pivot tables, what-if data tables, and links to other workbooks are not supported. The report flags them.
FAQ
Can an AI agent get exact numbers from my Excel model?
The hosted API returns calculated model outputs instead of asking the assistant to estimate them. Check the workbook first, and verify the agent's inputs, units, and interpretation.
Is there a WorkbookAPI MCP server today?
Yes, a local one. workbookapi-mcp runs on your computer and lets an AI assistant check a workbook, find its inputs and outputs, and calculate scenarios; the file stays on your machine. Install it with npx -y workbookapi-mcp (in Claude Code: claude mcp add workbookapi -- npx -y workbookapi-mcp). The hosted API is also available; see /docs/.
Does a matching check make the assistant's answer correct?
No. It checks formula results against saved Excel results for one input set. The model's assumptions and the agent's choice of inputs still need review.
Does my model leave my browser during the check?
No. The workbook never leaves your browser during the check. Only anonymous totals are counted, never values, formulas, or file names.
Read the privacy policy.
Start with your workbook
Check your workbook — free, it never leaves your browser
For the calculation workflow, see Excel to API. For many assumptions, see scenario analysis.