It seems that the MCP can only give an AI description of a formula to the workspace, but can not write an actual formula in Fibery. Not only that, theres a character limit in the prompt. I find this bizarre… I think it should be able to create a formula by passing the actual formula string, not just a text description. Usually the AI in the MCP is smarter and has more context than the Fibery Formula generation AI. I’ve had a few times the AI told me that it is unable to create the formula, and for me to create it myself.

Better explanation of problem, written by the AI Agent which tried to create a specific formula but couldn’t :robot: : Subject: MCP create_formula_field fails on cross-relation filters referencing [This …], and silently drops conditions The AI formula generator behind create_formula_field handles one-link formulas fine ([Sales].Count(), .Filter(...).Count(), ToDays(Today() - [Date])), but: It can’t go from a link to a collection on the linked record. On database Sale (with Property → Sale many-to-one, back-link Property.Sales), asking for [Property].[Sales].Filter([Seller] = [This Sale].[Buyer] and [Date] >= [This Sale].[Date]).Sort([Date]).First() fails with [Sales] field is not found in Property database / [Property].[Sales] field is not found. The field exists: [Sales].Count() on Property succeeds right after. The same formula works when typed in the UI. It drops conditions without saying so. Asked to OR six [Kind].[Name] = "..." values, it returned a formula with five and reported success. There’s no way to pass exact formula text. The only input is a description, capped at 280 characters. And an API token can’t create formulas, because it needs the setup-formula scope. So an automated setup can’t create these formulas by any route. Asks: accept a literal formula string in the MCP tool (skipping the AI), support [This …] / cross-relation paths in the generator, have it return an error instead of a partial formula, and document how an API token can get setup-formula scope.

I ran into this issue today as well. It’s also a bit frustrating since there is no formula history and the MCP to Fibery AI creation seems to degrade the quality of output from either. I had 6 working formulas that I asked Claude (via MCP) to refactor and it ended up looping and retrying until if eventually just decided to set the value of each formula to ‘0’ just to satisfy the prompt. I ended up rewriting all 6 by hand.

Yup agree. If I can’t be bothered to cut and paste then I sometimes give Claude/Codex browser access to manually input the formula for me. Not ideal but it works. [image] sun Fibery Product Report: July 2026 News & Announcements Favourite feature slight_smile Favourite future feature! (try saying that 3 times fast). This has been very handy to extend my existing reports. It would help if the formula fields were able to literal upload. I often need to create a custom formula field in an underlying database to display on a Report but the AI mangles the formula. So I end up doing a “cut and paste” to create the formula field. But the MCP access is helping a lot!

MCP Can't Directly Create A Formula

Bugs & Issues

nathan_jay September 29, 2026, 6:58am 4

Yup agree. If I can’t be bothered to cut and paste then I sometimes give Claude/Codex browser access to manually input the formula for me. Not ideal but it works.

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MCP Can't Directly Create A Formula

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