[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"skill-jetbrains-mps-aspect-actions":3,"mdc--5cedk9-key":32,"related-repo-jetbrains-mps-aspect-actions":1223,"related-org-jetbrains-mps-aspect-actions":1293},{"slug":4,"name":4,"fn":5,"description":6,"org":7,"tags":11,"stars":19,"repoUrl":20,"updatedAt":21,"license":22,"forks":23,"topics":24,"repo":27,"sourceUrl":30,"mdContent":31},"mps-aspect-actions","define and edit MPS node factories","Use when defining or editing MPS node factories (the \"actions\" aspect) — `NodeFactories` roots, per-concept `NodeFactory` setup functions that initialize a freshly created node and optionally copy data from a replaced `sampleNode`, plus the actions aspect's `CopyPasteHandlers` and `PasteWrappers` roots. Reach for this skill when a substitution, side transform, completion replacement, or `add new initialized(...)` should preserve fields from the node it is replacing, or when defaults set in a constructor are not enough.",{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},"jetbrains","JetBrains","https:\u002F\u002Fpexgzepcugksgbtrxkhf.supabase.co\u002Fstorage\u002Fv1\u002Fobject\u002Fpublic\u002Forg-logos\u002Fjetbrains.png",[12,16],{"name":13,"slug":14,"type":15},"Architecture","architecture","tag",{"name":17,"slug":18,"type":15},"Engineering","engineering",1650,"https:\u002F\u002Fgithub.com\u002FJetBrains\u002FMPS","2026-07-17T06:04:48.066901",null,311,[25,26],"domain-specific-language","dsl",{"repoUrl":20,"stars":19,"forks":23,"topics":28,"description":29},[25,26],"JetBrains Meta programming System","https:\u002F\u002Fgithub.com\u002FJetBrains\u002FMPS\u002Ftree\u002FHEAD\u002Fplugins\u002Fmcp-tools\u002Fresources\u002Fjetbrains\u002Fmps\u002Fagents\u002Fmcp\u002Fskills\u002Fmps-aspect-actions","---\nname: mps-aspect-actions\ndescription: Use when defining or editing MPS node factories (the \"actions\" aspect) — `NodeFactories` roots, per-concept `NodeFactory` setup functions that initialize a freshly created node and optionally copy data from a replaced `sampleNode`, plus the actions aspect's `CopyPasteHandlers` and `PasteWrappers` roots. Reach for this skill when a substitution, side transform, completion replacement, or `add new initialized(...)` should preserve fields from the node it is replacing, or when defaults set in a constructor are not enough.\ntype: reference\n---\n\n# MPS Actions Aspect\n\nThe **actions** aspect customizes how new nodes of a concept are constructed by the MPS editor — typically during substitution, side transformations, right-transform\u002F`\u003Cctrl-space>` replacement, or auto-replace. The framework produces an empty instance of the target concept; the setup function then populates it, often copying fields from the node it is replacing (`sampleNode`). Lives in `\u003Clang>\u002Fmodels\u002F\u003Clang>.actions.mps`, language `jetbrains.mps.lang.actions`. The aspect also hosts copy\u002Fpaste handlers and paste wrappers (see `references\u002Fcopy-paste-and-paste-wrappers.md`).\n\n## Critical Directives\n\n- One `NodeFactories` root per actions model; add per-concept `NodeFactory` children to it. Do not create one root per concept.\n- One `NodeFactory` per `applicableConcept`. Multiple factories for the same concept are not merged.\n- The setup function runs **before** `newNode` is attached to the model. `newNode.parent`, ancestors, and model-wide queries return null\u002Fempty. Use the `enclosingNode` implicit parameter when you need the would-be parent.\n- `sampleNode` is typed as `node\u003CBaseConcept>`. Always narrow with `ifInstanceOf (sampleNode is \u003CConcept> original)` before accessing fields — direct dereference will NPE or fail to compile.\n- Use `SPropertyAccess` (ref `property` → `PropertyDeclaration`) for properties; use `SLinkAccess` (ref `link` → `LinkDeclaration`) for **both** containment and reference child roles.\n- Factories do **not** fire for quotations `\u003CC()>`, `model.add root(\u003CC()>)`, `model.add new root(C)`, or pure rendering. If you need factory-initialised nodes in generator code, use `new node\u003CC>()` with explicit property assignments or route creation through an intention that calls `add new initialized`.\n- Edit factories through MPS MCP tools (`mps_mcp_insert_root_node_from_json`, `mps_mcp_update_node`, optionally `mps_mcp_parse_java_and_insert` with `featureKind: \"STATEMENTS\"` for the body). Do not hand-edit `.mps` files.\n- After editing, validate with `mps_mcp_check_root_node_problems` on the `NodeFactories` root and rebuild the language.\n\n## Common-Path Workflow\n\n1. Ensure an actions model exists (`\u003Clang>\u002Fmodels\u002F\u003Clang>.actions.mps`; create with `mps_mcp_create_model` and `modelName: \"\u003Clang>.actions\"` — aspect ID `actions`, case-sensitive, no `@` suffix; see [aspect-model-stereotypes.md](..\u002Fmps-mcp-workflow\u002Freferences\u002Faspect-model-stereotypes.md)). Used languages: `jetbrains.mps.lang.actions`, `jetbrains.mps.baseLanguage`, `jetbrains.mps.lang.smodel`. Add `jetbrains.mps.lang.core` as the base. Import the structure model of your language.\n2. Create the `NodeFactories` root via `mps_mcp_insert_root_node_from_json` (blueprint in `references\u002Fjson-blueprints.md`). Set `name`.\n3. For each concept that needs custom initialization, add a `NodeFactory` child via `mps_mcp_update_node`. Set `applicableConcept`; attach a `NodeSetupFunction` with a `StatementList` body.\n4. Fill the body. Typical pattern: `ifInstanceOf (sampleNode is \u003CConcept> original) { newNode.\u003Cprop> = original.\u003Cprop>; ... }`. Cross-type narrowing is allowed — see `references\u002Fsetup-function-bodies.md`.\n5. Validate with `mps_mcp_check_root_node_problems`, rebuild the language, exercise in a sandbox.\n\n## Implicit Parameters of `NodeSetupFunction`\n\n| Alias | FQN | Type | Nullable | Notes |\n|---|---|---|---|---|\n| `newNode` | `jetbrains.mps.lang.actions.structure.NodeSetupFunction_NewNode` | `node\u003CapplicableConcept>` | no | The freshly created empty node. Populate it. |\n| `sampleNode` | `jetbrains.mps.lang.actions.structure.NodeSetupFunction_SampleNode` | `node\u003CBaseConcept>` | yes | Node being replaced, if any. Narrow with `ifInstanceOf`. |\n| `enclosingNode` | `jetbrains.mps.lang.actions.structure.NodeSetupFunction_EnclosingNode` | `node\u003CBaseConcept>` | yes | Prospective parent container; null during root-node creation or programmatic creation outside the editor. |\n| `index` | `jetbrains.mps.lang.actions.structure.NodeSetupFunction_Index` | `int` | — | 0-based position in the parent collection, or 0 if not in a collection. |\n| `model` | (plain VariableReference in generated Java) | `SModel` | yes | The `SModel` `newNode` will be inserted into. Most factories don't use this. |\n\nSignature surfaced in the editor: `(newNode, sampleNode, enclosingNode, index, model) -> void`.\n\n## Related Skills\n\n- `mps-aspect-behavior` — concept constructors are the place to set defaults that don't depend on the node being replaced. Use a constructor for *intrinsic* defaults, a `NodeFactory` for context-sensitive carry-over.\n- `mps-aspect-intentions` — intentions that call `add new initialized(...)` route through factories. The `NF_*` family is documented in the intentions skill's `references\u002Ffactory-initialized.md`.\n- `mps-aspect-generator` — generator output bypasses factories (quotations and `add new root` do not fire factories). Document where the generator must mimic the factory behavior.\n- `mps-model-manipulation` — full smodel reference: `SLinkAccess` vs `SPropertyAccess`, `IfInstanceOfStatement`, `IfInstanceOfVariable`, and the `NF_*` family.\n- `mps-aspect-structure-concepts` — when adding the concept that `applicableConcept` targets.\n- `mps-aspect-constraints` — for `canBe*` rules that gate insertion before a factory ever runs.\n\n## Reference Index\n\n- Open `references\u002Fnode-factories-and-triggers.md` when you need the validated concept ref for `NodeFactories` \u002F `NodeFactory` \u002F `NodeSetupFunction`, the rule that factories are picked by exact `applicableConcept` (not by subtype inheritance through a more-general parent factory), and the precise list of triggers that fire \u002F do not fire a factory.\n- Open `references\u002Fsetup-function-bodies.md` when writing the function body — copying properties vs. child links (`SPropertyAccess` vs `SLinkAccess`), cross-type narrowing in `ifInstanceOf`, the verbatim ChemMastery (same-type property copy) and Kaja (cross-type child-link copy) examples, and the JSON shape for an `AssignmentExpression` over `SLinkAccess`.\n- Open `references\u002Fjson-blueprints.md` when inserting the `NodeFactories` root or a `NodeFactory` child via MCP — minimal blueprints, the full `IfInstanceOfStatement` body, and the tip on using `mps_mcp_parse_java_and_insert` to skip the blueprint.\n- Open `references\u002Fcopy-paste-and-paste-wrappers.md` when the language needs custom copy pre-processing, paste post-processing, or paste-time wrapping of nodes — these other roots also live in the actions aspect.\n- Open `references\u002Fconcept-reference.md` for the validated FQN\u002Fref table — the `jetbrains.mps.lang.actions` concepts plus the supporting BaseLanguage and smodel concepts used in setup bodies.\n- Open `references\u002Fcommon-failures.md` when a freshly created node always has defaults, `sampleNode.\u003Cprop>` does not compile, `enclosingNode` is unexpectedly null, the factory fires twice, or it does not fire from quotations \u002F generator code.\n",{"data":33,"body":35},{"name":4,"description":6,"type":34},"reference",{"type":36,"children":37},"root",[38,47,102,109,389,395,588,599,850,862,868,1033,1039],{"type":39,"tag":40,"props":41,"children":43},"element","h1",{"id":42},"mps-actions-aspect",[44],{"type":45,"value":46},"text","MPS Actions Aspect",{"type":39,"tag":48,"props":49,"children":50},"p",{},[51,53,59,61,68,70,76,78,84,86,92,94,100],{"type":45,"value":52},"The ",{"type":39,"tag":54,"props":55,"children":56},"strong",{},[57],{"type":45,"value":58},"actions",{"type":45,"value":60}," aspect customizes how new nodes of a concept are constructed by the MPS editor — typically during substitution, side transformations, right-transform\u002F",{"type":39,"tag":62,"props":63,"children":65},"code",{"className":64},[],[66],{"type":45,"value":67},"\u003Cctrl-space>",{"type":45,"value":69}," replacement, or auto-replace. 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Covers `jetbrains.mps.lang.editor` cell models (`CellModel_RefNode`\u002F`CellModel_RefNodeList`\u002F`CellModel_RefCell`\u002F`CellModel_Property`\u002F`CellModel_Constant`), layout choices, and JSON blueprints for common editor shapes. For the non-layout side (action maps, keymaps, transformation\u002Fsubstitute menus) use `mps-aspect-editor-menus-and-keymaps`.",{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1276,1279],{"name":1277,"slug":1278,"type":15},"Design","design",{"name":1280,"slug":1281,"type":15},"UI Components","ui-components","2026-07-23T05:41:56.638151",{"slug":1284,"name":1284,"fn":1285,"description":1286,"org":1287,"tags":1288,"stars":19,"repoUrl":20,"updatedAt":1291},"mps-aspect-editor-menus-and-keymaps","author MPS editor menus and keymaps","Use when authoring the **non-layout** parts of the MPS editor aspect — what happens when the user types, presses a key, triggers completion, pastes, or invokes a context action. Covers action maps (`CellActionMapDeclaration`), cell keymaps (`CellKeyMapDeclaration`), transformation menus (`TransformationMenu_Default` \u002F `_Named` \u002F `_Contribution`), substitute menus (`SubstituteMenu_Default` \u002F `SubstituteMenu` \u002F contributions), side transforms (LEFT\u002FRIGHT), legacy cell menus, paste wrappers and copy-paste handlers (in the actions language), completion styling, reference presentation, two-step deletion, and the editor selection API. Trigger terms: `actionMap`, `keyMap`, `delete_action_id`, `transformationMenu`, `substituteMenu`, `Ctrl+Space`, `Ctrl+Alt+B`, side transform, paste wrapper, completion styling, `PasteWrappers`, `CopyPasteHandlers`. For the **layout** side (cells, layouts, style sheets) use `mps-aspect-editor` instead.",{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1289,1290],{"name":17,"slug":18,"type":15},{"name":1280,"slug":1281,"type":15},"2026-07-23T05:41:49.666535",31,{"items":1294,"total":1378},[1295,1301,1306,1311,1316,1320,1325,1330,1339,1348,1356,1369],{"slug":1226,"name":1226,"fn":1227,"description":1228,"org":1296,"tags":1297,"stars":19,"repoUrl":20,"updatedAt":1236},{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1298,1299,1300],{"name":13,"slug":14,"type":15},{"name":1233,"slug":1234,"type":15},{"name":17,"slug":18,"type":15},{"slug":4,"name":4,"fn":5,"description":6,"org":1302,"tags":1303,"stars":19,"repoUrl":20,"updatedAt":21},{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1304,1305],{"name":13,"slug":14,"type":15},{"name":17,"slug":18,"type":15},{"slug":879,"name":879,"fn":1243,"description":1244,"org":1307,"tags":1308,"stars":19,"repoUrl":20,"updatedAt":1249},{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1309,1310],{"name":13,"slug":14,"type":15},{"name":17,"slug":18,"type":15},{"slug":1022,"name":1022,"fn":1251,"description":1252,"org":1312,"tags":1313,"stars":19,"repoUrl":20,"updatedAt":1259},{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1314,1315],{"name":13,"slug":14,"type":15},{"name":1257,"slug":1258,"type":15},{"slug":1261,"name":1261,"fn":1262,"description":1263,"org":1317,"tags":1318,"stars":19,"repoUrl":20,"updatedAt":1269},{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1319],{"name":1267,"slug":1268,"type":15},{"slug":1271,"name":1271,"fn":1272,"description":1273,"org":1321,"tags":1322,"stars":19,"repoUrl":20,"updatedAt":1282},{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1323,1324],{"name":1277,"slug":1278,"type":15},{"name":1280,"slug":1281,"type":15},{"slug":1284,"name":1284,"fn":1285,"description":1286,"org":1326,"tags":1327,"stars":19,"repoUrl":20,"updatedAt":1291},{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1328,1329],{"name":17,"slug":18,"type":15},{"name":1280,"slug":1281,"type":15},{"slug":1331,"name":1331,"fn":1332,"description":1333,"org":1334,"tags":1335,"stars":19,"repoUrl":20,"updatedAt":1338},"mps-aspect-generation-plan","modify MPS generation plans","Use when defining or modifying an MPS generation plan — explicit ordering of generators, checkpoints for cross-model reference resolution, forks for parallel branches, IncludePlan composition, conditional PlanContribution activation, ParameterEquals\u002FConceptListSelector fork selectors, and InitModelAttributes for targetFacet routing. Apply when working with @genplan models, the jetbrains.mps.lang.generator.plan language, attaching plans via DevKits or the Custom generation facet, or debugging cross-model mapping label resolution.",{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1336,1337],{"name":13,"slug":14,"type":15},{"name":17,"slug":18,"type":15},"2026-07-13T06:44:59.507855",{"slug":939,"name":939,"fn":1340,"description":1341,"org":1342,"tags":1343,"stars":19,"repoUrl":20,"updatedAt":1347},"define JetBrains MPS generator rules","Use when defining or modifying MPS generators — author a generator module, add or edit root\u002Freduction\u002Fweaving\u002Fpattern mapping rules, attach template macros ($COPY_SRC, $LOOP, $IF, $PROPERTY, $REF, $SWITCH, $MAP_SRC, $WEAVE, $INSERT, $LABEL, $TRACE, $VAR), wire mapping labels, build template switches, write pre\u002Fpost mapping scripts, navigate `genContext`, or debug \"rule didn't fire\", missing references, empty output, infinite reduction loops, and generated-Java compile failures.",{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1344,1345,1346],{"name":13,"slug":14,"type":15},{"name":1257,"slug":1258,"type":15},{"name":17,"slug":18,"type":15},"2026-07-17T06:06:58.042999",{"slug":905,"name":905,"fn":1349,"description":1350,"org":1351,"tags":1352,"stars":19,"repoUrl":20,"updatedAt":1355},"define and edit MPS intentions","Use when defining or editing MPS intentions (the Alt+Enter context-action aspect) — adding `IntentionDeclaration` roots, parameterized or surround-with variants, description\u002FisApplicable\u002Fexecute blocks, child-filter functions, factory-initialized AST splicing, or debugging why an intention is not offered. Lives in the language's `intentions` model and uses `jetbrains.mps.lang.intentions`.",{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1353,1354],{"name":13,"slug":14,"type":15},{"name":17,"slug":18,"type":15},"2026-07-23T05:41:48.692899",{"slug":1357,"name":1357,"fn":1358,"description":1359,"org":1360,"tags":1361,"stars":19,"repoUrl":20,"updatedAt":1368},"mps-aspect-migrations","author and debug MPS migration scripts","Use when authoring or debugging MPS migration scripts that upgrade user models after a language definition changes — covers jetbrains.mps.lang.migration (MigrationScript class-based, PureMigrationScript declarative, MoveConcept\u002FMoveContainmentLink\u002FMoveReferenceLink\u002FMoveProperty, ordering via OrderDependency, data exchange via putData\u002FgetData, RefactoringLog, ConceptMigrationReference) and jetbrains.mps.lang.script Enhancement Scripts (MigrationScript with MigrationScriptPart_Instance, ExtractInterfaceMigration, FactoryMigrationScriptPart, CommentMigrationScriptPart) — when a model needs version-gated upgrade, concept rename or removal, link or property rename, instance-level transformation, or composition of migration steps.",{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1362,1365],{"name":1363,"slug":1364,"type":15},"Debugging","debugging",{"name":1366,"slug":1367,"type":15},"Migration","migration","2026-07-13T06:45:20.372122",{"slug":1004,"name":1004,"fn":1370,"description":1371,"org":1372,"tags":1373,"stars":19,"repoUrl":20,"updatedAt":1377},"define concepts in MPS structure aspect","Define concepts, interface concepts, enumerations, and constrained data types in an MPS language's `structure` aspect. Covers smart-reference detection, alias rules, cardinality, INamedConcept usage, bulk creation, and the full `mps_mcp_alter_structure` \u002F `mps_mcp_query_structure` reference. Use when authoring or modifying a language's structure model.",{"slug":8,"name":9,"logoUrl":10,"githubOrg":9},[1374],{"name":1375,"slug":1376,"type":15},"Data Modeling","data-modeling","2026-07-23T05:41:30.705975",188]