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Free class, quiz and certificate
Train Your FileMaker AI Agent
A free class for experienced FileMaker Developers, from your first Skill to a Skill library you publish. Ten lessons, then an open book quiz with a certificate at 80%.
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01: Build Your First FileMaker Skill
'A Skill is context, not magic.' ~ my good-self, Reconnect 2026.
You explain the same FileMaker rule to Claude every week. Your script naming, your opening steps, the way you like a result returned. Then the next chat starts cold, and you explain it again.
This lesson assumes you've never built, installed or even seen a Skill. By the end you'll have written one, in a plain Claude chat, and watched Claude use it without being asked.
In this post:
Why Claude Invents FileMaker Functions
Example: I asked Claude for a script that sets a variable from field data. It came back with GetContents ( ). When I pushed back, it said the function had been deprecated in FileMaker 19. It never existed.
That's not a Claude problem. That's a context problem. The Agent only knows what's in front of it, and nobody put your FileMaker knowledge there. A Skill does.
What a FileMaker Skill Is
A Skill is a folder of instructions and reference files, with a file called SKILL.md at the top. Claude loads it only when the task calls for it. So the Agent knows what you know, how you work, and why.
It's worth considering Skills as the agentic version of Brian Dunning's shared custom functions: written once, called by name, used everywhere.
SKILL.md has two parts. The frontmatter at the top holds a name and a description. The body below holds the instructions. When Claude decides which Skill to use, it reads every description and nothing else. The body loads only once the Skill has fired.
In FileMaker terms, the description is the script name and comment header you scan in the Scripts workspace. Nobody runs a script they can't find.
What you need. Claude Desktop in chat, or claude.ai. No Code tab, nothing to install, and no Skill experience. I built my first FileMaker Skills in chat, for about a month, before I went anywhere near the Code tab.
One rule worth writing down. Small beats ambitious. Pick the rule you keep repeating to Claude. Mine is script naming: Domain: Action, so the script is Email: Invoice To Contact, never Email Invoice To Contact.
Step 1: Ask Claude to Interview You
Open a new chat and start with a trimmed version of the prompt I use on stage:
Let's create a Skill together.
First ask me what the skill should do . . .
Then answer its questions. What the rule is, when it applies, an example of right and wrong. Like any software project, you won't know exactly what you're after until you're in it. That's fine. A first version is a first version.
Step 2: The Skill Limits Claude Doesn't Know
Before Claude writes a line, give it the limits the upload enforces. Claude doesn't know them.
Name. Lowercase letters, numbers and hyphens, 64 characters at most, and never 'claude' or 'anthropic'.
Description. 1,024 characters at most, and no angle brackets.
Body. Under 500 lines. Less is better.
Example: Back in June, Claude wrote me Skills that just wouldn't load. Even Anthropic's own skill-creator Skill produced ones that failed on upload, because it didn't know these limits either. Hence I built a Skill to build Skills, recursive as that sounds. That's a later lesson.
Step 3: Write a Description That Fires
The description decides whether your Skill is ever used. Three parts, in this order:
What it does, in the third person.
'Use when', followed by the words you actually type.
'Not for', naming the nearest neighbours.
A sketch for a naming Skill:
---
name: filemaker-script-naming
description: >-
Applies my FileMaker script naming convention, Domain: Action, when
writing, naming or renaming scripts. Use when naming a script, reviewing
script names, or asked what to call a script. Not for table, field or
layout names, or calculation syntax.
---
Put the rule that matters in the description, not just the body.
Example: When I reviewed my claris-filemaker-pro Skill against Anthropic's best practices, a 'mandatory trigger' rule sat in the body. Claude only reads the body after the Skill has fired, so the rule did nothing. It moved into the description. The full story is in FileMaker Knowledge Delegation.
Step 4: Upload Your FileMaker Skill
Ask Claude for the finished Skill as a .zip. Check one thing before you upload: inside the zip sits one folder, named exactly as the Skill, with SKILL.md inside it. Nothing wrapped around it, nothing else beside it.
Then, in Claude Desktop or claude.ai, open Customize, then Skills, and upload the .zip. The same screen turns a Skill on or off.
Step 5: Check Your Skill Fires
Start a fresh chat and ask a question that needs your rule, without naming the Skill:
What should I call a script that emails an invoice to the contact?
Then ask Claude which Skill it used for that answer. If it names yours, the description works. If it doesn't, the fix is almost always the description: add the words you actually typed to its 'Use when'.
Naming the Skill in your prompt also works, and gets its direct attention. The other ways to call a Skill come in the next lesson.
Skill Vocabulary for FileMaker Developers
Skill. A folder of instructions and reference files, with a SKILL.md at the top, that the Agent loads when the task calls for it.
SKILL.md. The file Claude reads first: frontmatter at the top, instructions below.
Frontmatter. The block between the --- lines at the top of SKILL.md, holding the name and description.
Description. The paragraph Claude reads to decide whether to use a Skill, and the only part it sees until then.
Body. The instructions below the frontmatter, read only after the Skill fires.
Upload. Adding your own Skill's .zip under Customize, then Skills.
Takeaway
Context, not magic. Your Skill knows exactly what you wrote down, and nothing more. One rule, one description that uses your own words, inside the limits Claude doesn't know, uploaded and checked. That's a FileMaker Skill.
Next, two kinds of Skill: what the Agent knows, and how it works. Continue with my next post, FileMaker Reference Skills and Workflow Skills.
More to come . . .
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