Add Delimit — API breaking change detection (27 types) (#718)

Co-authored-by: infracore <infracore@delimit.ai>

Author: infracore

src/content/tools/delimit.md

@@ -0,0 +1,48 @@
+---
+name: Delimit
+description: |
+  Catch breaking API changes before merge. 27 detection types (17 breaking, 10 non-breaking), semver classification, migration guides, and policy enforcement for OpenAPI specs. Works as a GitHub Action, CLI, and MCP server for AI coding assistants.
+categories:
+  - linting
+  - testing
+link: https://delimit.ai
+languages:
+  any: true
+repo: https://github.com/delimit-ai/delimit
+oaiSpecs:
+  oas: true
+  overlays: false
+  arazzo: false
+oasVersions:
+  v2: true
+  v3: true
+  v3_1: true
+  v3_2: false
+---
+
+## Overview
+
+Delimit detects breaking API changes in OpenAPI specs with 27 change types — deterministic rules, not AI inference. Same input always produces the same result.
+
+## Features
+
+- **GitHub Action** — runs on every PR, posts severity-graded comments with migration guides
+- **CLI** — `npx delimit-cli lint`, `diff`, `explain` for local development
+- **MCP Server** — 81 tools for AI coding assistants (Claude Code, Codex, Cursor, Gemini CLI)
+- **Policy enforcement** — custom rules in `.delimit/policies.yml` with presets (strict/default/relaxed)
+- **Semver classification** — deterministic MAJOR/MINOR/PATCH/NONE recommendation
+
+## Usage
+
+```yaml
+# GitHub Action
+- uses: delimit-ai/delimit-action@v1
+  with:
+    spec: api/openapi.yaml
+```
+
+```bash
+# CLI
+npx delimit-cli lint old.yaml new.yaml
+npx delimit-cli diff old.yaml new.yaml
+```