--- title: "Engineering articles and guides — Elva blog · Elva" description: "Engineering notes from building Elva: how a repo becomes a catalog, how agents call APIs, and what the numbers said. 4 guides, newest first." canonical: "https://getelva.ai/blog/tag/engineering" lastModified: "2026-09-02T16:58:18.662Z" --- 1. [Blog](https://getelva.ai/blog.md) 2. Engineering # Engineering articles and guides Engineering notes from building Elva: how a repo becomes a catalog, how agents call APIs, and what the numbers said. How static analysis reads route handlers and validators, how agent-readiness is scored, and where MCP and REST genuinely differ — written from the code. 4 posts, newest first · Updated 2026-09-01 [ OpenAPI Aug 27, 2026 How to generate an OpenAPI spec from existing code Four working ways to get an OpenAPI 3.1 spec out of a codebase that never had one, what each approach misses, and how to keep the result true. 4 min read ](https://getelva.ai/blog/generate-openapi-spec-from-code.md)[ MCP Aug 27, 2026 MCP vs REST: what changes when agents call your API MCP does not replace REST. It changes who the caller is. What that shift means for interface design, auth, error messages, and operations. 4 min read ](https://getelva.ai/blog/mcp-vs-rest-api.md)[ Engineering Jul 2, 2026 How Elva reads a repo: from route handlers to OpenAPI 3.1 Static analysis, framework fingerprints, and the messy middle where code and spec disagree. 11 min read ](https://getelva.ai/blog/how-elva-reads-a-repo.md)[ Engineering Jun 5, 2026 Scoring agent readiness: what the A–E grade actually measures Description coverage, schema completeness, auth clarity, and the weights behind the grade. 9 min read ](https://getelva.ai/blog/scoring-agent-readiness.md) ALL TOPICS [MCP9](https://getelva.ai/blog/tag/mcp.md) [Governance7](https://getelva.ai/blog/tag/governance.md) [AI Agents5](https://getelva.ai/blog/tag/ai-agents.md) [OpenAPI5](https://getelva.ai/blog/tag/openapi.md) [Contracts4](https://getelva.ai/blog/tag/contracts.md) [Engineering4](https://getelva.ai/blog/tag/engineering.md) [Observability4](https://getelva.ai/blog/tag/observability.md) [Product3](https://getelva.ai/blog/tag/product.md) [Infrastructure2](https://getelva.ai/blog/tag/infrastructure.md) ## Ship notes, monthly One email with what shipped and what we learned. Unsubscribe anytime. ## Ship APIs anything can call Humans, tests, partners, agents. One catalog, one contract, one place. [Sign up free](https://app.getelva.ai/signup) [Read the blog](https://getelva.ai/blog.md)