MetaEngine

Semantic code generation for TypeScript, Python, Go, C#, Java, Kotlin, Groovy, Scala, Swift, PHP, and Rust. Generates compilable source files with perfect imports and cross-references from structured JSON specs. # MetaEngine MCP — AI Code Generation Guide MetaEngine is a semantic code generation system exposed via MCP. You describe types, relationships, and methods as structured JSON — MetaEngine produces compilable, correctly-imported source files for TypeScript, C#, Python, Go, Java, Kotlin, Groovy, Scala, Swift, and PHP. Unlike templates, it resolves cross-references, manages imports, and handles language idioms automatically. This matters for AI usage because a single well-formed JSON call replaces dozens of error-prone file writes. --- ## Critical Rules These are the rules that cause the most failures when violated. Read them first. ### 1. Generate ALL related types in ONE call `typeIdentifier` references only resolve within the current batch. If `UserService` references `User`, both must be in the same `generate_code` call. ```jsonc // ONE call with both types { "classes": [ {"name": "User", "typeIdentifier": "user", ...}, {"name": "UserService", ...references "user"...} ] } ``` ### 2. Properties = type declarations. CustomCode = everything else. `properties[]` declares fields with types only. `customCode[]` handles methods, initialized fields, and any code with logic. One `customCode` item = exactly one member. ```jsonc // Property: type only, no initialization "properties": [{"name": "id", "primitiveType": "String"}] // CustomCode: method or initialized field "customCode": [ {"code": "private http = inject(HttpClient);"}, {"code": "getAll(): T[] { return this.items; }"} ] ``` **Never put methods in properties.** Never put uninitialized type declarations in customCode. ### 3. Use templateRefs for internal types in customCode When customCode references a type from the same batch, use `$placeholder` syntax with `templateRefs`. Th…

Generates a fully typed HTTP client from a GraphQL SDL schema. Supports Angular, React, TypeScript Fetch, Go, Java Spring, C#, Kotlin, Python, Rust, and Swift. Enable `fragments` to emit reusable named GraphQL fragments for object-type selections.

Generate HTTP clients from OpenAPI specifications for 10 frameworks: Angular, React, TypeScript Fetch, Go net/http, Java Spring, Python httpx, C# HttpClient, Kotlin Ktor, Rust Reqwest, Swift URLSession. Provide an inline OpenAPI spec (YAML/JSON) or a URL, choose a framework, and get fully typed, production-ready HTTP client code with models, services, and error handling.

Generates a fully typed HTTP client from Protocol Buffers (.proto) definitions. Supports Angular, React, TypeScript Fetch, Go, Java Spring, C#, Kotlin, Python, Rust, and Swift.

Generates typed model classes from SQL DDL (CREATE TABLE statements). Supports TypeScript, C#, Go, Python, Java, Kotlin, Groovy, Scala, Swift, PHP, and Rust.

Load code generation spec from a JSON file - Perfect for complex architectures and reusable templates! Instead of constructing large JSON specs in memory, load them from version-controlled .json files. All the same functionality as generate_code (outputPath, skipExisting, dryRun) but with zero memory overhead. Benefits: - Drastically reduced AI context usage (just pass file path!) - Version control your architecture patterns - Reusable templates across projects - Supports complex multi-file generations without context bloat Usage: 1. Create a .json file with your spec (same structure as generate_code) 2. Call this tool with the file path 3. Optionally override outputPath, skipExisting, or dryRun Example spec file (user-system.json): { "language": "typescript", "classes": [{"name": "User", ...}], "interfaces": [{...}] } Then call: load_spec_from_file({specFilePath: "specs/user-system.json", outputPath: "src"})

Returns essential MetaEngine patterns and documentation resources. This helper tool provides AI assistants with critical MetaEngine concepts: - The fundamental principle of generating related types in ONE call - Properties vs customCode distinction - Template references and type referencing patterns - Language-specific best practices Returns links to comprehensive documentation with patterns and examples. Call this when you need guidance or are generating code for the first time.