mops

mops is a small helper CLI for helping LLMs work with JetBrains MPS models.

Usage

mops expand < input.mps > output.mps
mops expand input.mps > output.mps
mops generate-ids model.mps 10
mops generate-ids --long model-folder 10
mops list-models
mops validate [--json] <model.mps|model-folder|root.mpsr> [other-targets...]
mops --version

Diagnostics are written to stderr. Malformed XML, unsupported persistence versions, invalid persistence containment shape, missing registries, and duplicate registry/import indices fail with a non-zero exit code.

Commands

mops expand [input.mps]

Expands short indices in the MPS model XML to human-readable identifiers or long IDs, so the model is easier to inspect with humans or LLMs.

It rewrites selected node-graph attributes using the model's own <registry> and <imports> sections:

• node@concept becomes the full concept name.
• node@role, property@role, and ref@role become unqualified role names.
• regular MPS node IDs in node@id, ref@node, and ref@to become signed decimal Java long values.
• import aliases in ref@to become the full imported model reference.

The <registry> subtree is left semantically unchanged.

Reads from stdin when input.mps is omitted. Writes transformed XML to stdout.

mops generate-ids [--long] <model.mps|model-folder> <count>

Generates regular node IDs that are not already used by node@id attributes in the model. For standalone persistence, pass a .mps file. For file-per-root persistence, pass the model folder; direct *.mpsr files in that folder are scanned.

IDs are printed one per line. By default they use MPS Java-friendly base64 format. With --long, they are printed as decimal int64 values. Command flags must appear before positional arguments.

mops list-models [root]

Scans root, or the current directory when omitted, for standalone .mps model files and file-per-root .model metadata files. Prints a pretty JSON object mapping model IDs to absolute paths. When multiple locations have the same model ID, the value is an array of paths instead of a string.

File-per-root models are reported as the parent folder of the .model file with a trailing /. Paths are normalized to / separators.

When possible, list-models uses git ls-files -co --exclude-standard so Git-ignored files are skipped. If Git is unavailable or the root is not in a Git worktree, it falls back to a filesystem walk and only skips .git.

mops validate [--json] <model.mps|model-folder|root.mpsr> [other-targets...]

Validates explicit MPS model XML targets. Standalone .mps files and file-per-root model folders are complete validation targets. For file-per-root persistence, pass the model folder containing .model; direct *.mpsr files are checked as one model-wide target and nested *.mpsr files are ignored.

Passing a single *.mpsr runs incomplete validation, which reports a non-blocking informational finding and tells the caller to validate the file-per-root model folder containing .model for complete structural validation. Incomplete validation does not fail solely because sibling roots are unavailable. Well-formed persistence version 9 targets pass. Malformed XML and unsupported persistence versions are reported as validation findings, and every requested target is checked before the final exit status is decided.

Human output is terse. With --json, validate prints a stable validation report with status and findings for LLM consumption.

Build And Test

./gradlew check

cd cli
go test ./...
go build ./cmd/mops

The repository is a Gradle-rooted monorepo. cli/ contains the Go module named mops; direct Go workflows run from that directory. ide/ contains the MPS project home for the future Live IDE bridge artifact. Root Gradle tasks orchestrate subproject checks without replacing Go dependency management or build semantics.

Attribution

The regular node ID decoding follows the behavior of JetBrains MPS persistence v9 IdEncoder and JavaFriendlyBase64.

• https://github.com/JetBrains/MPS/blob/9b2eefc0208fecedb3e08c7d9f7f53aa22b5e72e/core/persistence/source/jetbrains/mps/smodel/persistence/def/v9/IdEncoder.java
• https://github.com/JetBrains/MPS/blob/9b2eefc0208fecedb3e08c7d9f7f53aa22b5e72e/core/smodel/source/jetbrains/mps/smodel/JavaFriendlyBase64.java