# API Contract Safety

> Preserve and evolve ASP.NET Core API contracts safely. Use when changing routes, verbs, headers, parameters, DTOs, JSON, status/errors, enums, auth, versioning, or public interfaces.

- Skill: `dprakash2101/api-contract-safety` (Agent Skill)
- Install (CLI): `npx skillmds@latest add dprakash2101/api-contract-safety`
- Raw SKILL.md: https://api.skillmd.com/api/skills/dprakash2101/api-contract-safety/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: dprakash2101 (https://skillmd.com/u/dprakash2101)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/dprakash2101/api-contract-safety

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# API contract safety

Treat routes, verbs, headers, query/path parameters, request and response schemas, JSON names, serialization rules, status codes, error bodies, enums, auth requirements, and public interfaces as contracts.

Before editing, locate controller/endpoint definitions, DTOs, serializers/converters, validators, OpenAPI generation, clients, contract/integration tests, and known consumers. Record current observable behavior, including defaults, optionality, casing, null handling, and error responses.

Prefer additive, backward-compatible changes. Do not rename/remove fields, change type or meaning, make optional input required, alter enum wire values, change status/error behavior, or tighten auth unless required. Distinguish missing, null, empty, and default values when clients can observe the difference.

When a breaking change is unavoidable, identify affected consumers and use the repository's versioning/migration/deprecation approach. Test serialized wire behavior and representative failures, not only C# object equality. Update API documentation/generated clients only when part of the repository's established workflow.