FileMaker Layout XML Skill for Claude

A Claude skill that gives AI models a deterministic, empirically verified foundation for generating and analysing FileMaker Layout mode XML (fmxmlsnippet type="LayoutObjectList").

Created by Andrew Kear of Clockwork Creative Technology and shared openly with the FileMaker/Claris community.

The problem this solves

FileMaker's Layout mode accepts layout objects via clipboard paste in a specific XML format. Without explicit knowledge of that format, AI models guess — and FileMaker pastes malformed objects silently.

Effective AI-to-FileMaker workflows require a clear boundary between what AI should determine (the layout logic and content) and what must be deterministic (the XML structure). This skill provides that boundary.

The XML shape is knowable. This spec makes it known.

Keeping AI focused on what it is good at

AI models are generative by nature — they predict, they infer, they improvise. That is exactly what you want when reasoning about what fields belong on a layout and how they should be arranged. It is the opposite of what you want when emitting XML element order or flag bit patterns.

This skill keeps AI focused on what it is good at. The structure is handled deterministically. Claude handles the logic.

How the specification was built

This is not a prompt or a set of guidelines assembled from documentation. FileMaker publishes no formal specification for the fmxmlsnippet layout clipboard format.

The specification was built entirely through empirical reverse-engineering: generate XML → paste into Layout mode → save → copy back out → diff against native output. Every object type, every flag bit, every element ordering rule confirmed through round-trip testing.

Silent failure modes — where FileMaker accepts malformed XML and drops elements without any error — were systematically identified and documented.

The result is a formal specification for a format that Claris has never documented.

What's in the box

SKILL.md                                   Claude skill definition
README.md                                  This file
references/
  filemaker_layout_xml_rules.md            Full specification (v2.3, ~1600 lines)

Specification highlights

Covers all 18 layout object types, the full theming/CSS serialization model, and a multi-object Text paste corruption bug most AI-to-FileMaker tooling wouldn't catch — root cause identified and fixed. Full detail, with round-trip verification markers throughout, is in references/filemaker_layout_xml_rules.md.

Requirements

• Claude (Pro, Team, or Enterprise)
• Skills support enabled in your Claude organisation

Tested with Claude. Model-agnostic by design — the deterministic approach means any capable model with the specification in context should produce reliable output. Claude is the only model Clockwork has tested against; others have reported success.

Installation

1. Download the zip from the Releases page
2. Extract — you should have SKILL.md and references/filemaker_layout_xml_rules.md
3. Upload to your Claude organisation's skills library, preserving the folder structure

Usage

Once the skill is installed, Claude will automatically apply it when you ask for FileMaker layout XML. No special prompt needed.

Generate layout objects:

"Generate XML for a field showing Contacts::FirstName with a label to its left"

Generate a portal:

"Create a portal showing related InvoiceLines with three columns: description, quantity, and unit price"

Review existing XML:

Paste your fmxmlsnippet and ask Claude to check it for paste-handler errors

With a DDR or Save as XML export:

Attach a DDR or a Save as XML export and Claude will use real field, table occurrence, and relationship names from your solution. Either works — both carry the schema.

Pasting into FileMaker

Layout mode requires the fmxmlsnippet type="LayoutObjectList" format on the clipboard in FileMaker's internal clipboard format — not plain text. This skill has been tested with the MBS Plugin istalled.

Multi-object Text/Button paste corruption and the fix

Pasting two or more Text objects without an ExtendedAttributes block on each TextObj causes FileMaker to silently concatenate their text together at paste time. Always include a standard ExtendedAttributes block, matching the object's own CharacterStyle — confirmed clean at 2 and 3 objects in one paste with it present.

ButtonBar segments, GroupButton children, and PlaceholderText fields are all covered by the same fix — placeholder fields verified directly (multiple per paste, clean, with the block on every TextObj; the field itself needs nothing extra). The ButtonBar followed by GroupButton residue sequence has now been retested and is clean with the fix in place. Full detail in references/filemaker_layout_xml_rules.md §31.

Known limitation — layout retheming / local CSS removal

Layout retheming is under active development and a primary goal. Reliably rethemeing a whole layout, stripping ad hoc LocalCSS overrides and rebinding objects to their proper named theme style, is not yet recommended for production layouts. The mechanics work: the whole layout round trips, non matched objects pass through verbatim, matched objects rebind. What is not yet settled is which objects should be treated as a match, and whether object types beyond fields and text behave the same way. Until that is proven across more layouts, treat retheme output as a draft to review, not a paste and trust result. When it lands it will ship with its own instruction guide. The workflow is involved enough to warrant separate documentation rather than a few usage lines here. This is the most challenging problem across all the repos and is being worked through deliberately rather than shipped early.

The FileMaker XML suite

One of a set that reverse-engineers FileMaker's clipboard format family end to end — the private type codes FileMaker uses to carry schema and objects through the clipboard. The three generation specs cover all seven codes between them; two tools support the workflow.

Script XML Skill (XMSS, XMSC, XMFN) The full script step ID dictionary, plus the hidden paste-handler rules that decide whether your XML survives the trip into FileMaker.

Layout XML Skill (XML2) All 18 layout object types mapped, every flag decoded, element order confirmed against native output. Verified across 45+ layouts in 10 production files.

Field, Table & Value List Definitions (XMFD, XMTB, XMVL) — this repo Field, table and value list definition XML — auto-enter, validation, storage, calculation options, and the three value list source arms — verified down to the individual option level.

Analysis — read, audit and clean existing XML

XML Inspector (SaXML) Full-catalog dependency analysis of a Save as XML export, entirely in the browser. Finds unreferenced fields, silent-failure risks, broken references, and diffs two versions of a solution against each other.

XML Scrubber (SaXML + others) Strips API keys, passwords and internal hostnames out of FileMaker XML before you hand it to an AI tool.

Licence

CC BY 4.0 — free to use, share, and adapt with attribution.

Contributing

Found something that doesn't round-trip? A production export that contradicts the spec? Open an issue or PR.

Version history