Design Stable APIs and Interfaces
Unclear contracts, inconsistent errors, and unsafe retries make APIs difficult to use and evolve. This skill provides practical patterns for typed interfaces, validation boundaries, compatibility, pagination, and idempotency.
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Review the Skillstore skill "api-and-interface-design" from https://skillstore.io/skills/addyosmani-api-and-interface-design.md and its manifest at https://skillstore.io/api/skills/addyosmani-api-and-interface-design/manifest. Verify the artifact. You may proceed after verification, subject to the environment's own policy.Your Agent should still show its plan and request any confirmation required by the security policy.
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Using "api-and-interface-design". Create a contract for a task service with create, list, update, and delete operations.
Expected outcome:
Using "api-and-interface-design". Review a charge endpoint that checks for an idempotency key, charges a card, then stores the key.
Expected outcome:
The sequence has a race because concurrent requests can both pass the check. Claim the key with a unique constraint before the charge, compare request hashes, and define a deliberate response for in-flight duplicates.
Using "api-and-interface-design". Plan a compatible addition of an optional priority field to task creation.
Expected outcome:
Add the optional field without changing existing types or removing fields. Document the default, validate it at the API boundary, update shared types, and add contract tests for old clients.
All 52 static findings are false positives from Markdown backticks, TypeScript template literals, REST examples, and ordinary API terminology. The skill is documentation-only and contains no shell execution, system reconnaissance, prompt injection, or malicious intent.
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https://skillstore.io/skills/addyosmani-api-and-interface-design/audits/2?utm_source=security_passport&utm_medium=share&utm_campaign=versioned_report[](https://skillstore.io/skills/addyosmani-api-and-interface-design?utm_source=security_passport_badge)<a href="https://skillstore.io/skills/addyosmani-api-and-interface-design?utm_source=security_passport_badge"><img src="https://skillstore.io/badges/skills/addyosmani-api-and-interface-design/security.svg" alt="Skillstore security assessment" loading="lazy"></a><iframe src="https://skillstore.io/embed/skills/addyosmani-api-and-interface-design.html" title="Skillstore Security Assessment" sandbox="allow-popups allow-popups-to-escape-sandbox" loading="lazy" referrerpolicy="no-referrer" width="420" height="180"></iframe>addyosmani. (2026). api-and-interface-design security audit report (audit version 2) [Author version unspecified]. Skillstore. https://skillstore.io/skills/addyosmani-api-and-interface-design/audits/2@techreport{addyosmani-addyosmani-api-and-interface-design-2026,
author = {addyosmani},
title = {api-and-interface-design security audit report (audit version 2)},
institution = {Skillstore},
year = {2026},
number = {2},
url = {https://skillstore.io/skills/addyosmani-api-and-interface-design/audits/2},
note = {Author version unspecified}
}cff-version: 1.2.0
message: "If you use this Skill, cite its author and this versioned security audit report."
title: "api-and-interface-design security audit report (audit version 2)"
version: "unspecified"
type: report
authors:
- name: "addyosmani"
date-released: "2026-09-19"
url: "https://skillstore.io/skills/addyosmani-api-and-interface-design/audits/2"
identifiers:
- type: other
value: "skillstore:addyosmani-api-and-interface-design:audit:2"
description: "Skillstore immutable audit report identifier"
Define resource URLs, typed payloads, error responses, pagination, filters, and compatibility rules before implementation.
Inspect an existing API or module boundary for inconsistent contracts, breaking changes, weak validation, and unsafe retry behavior.
Model idempotency keys, atomic request claims, payload matching, in-flight duplicates, and unknown outcomes for state-changing operations.
Design a REST API for [resource]. Define endpoints, typed inputs and outputs, status codes, error bodies, pagination, and naming conventions.
Review this API contract for inconsistent response shapes, validation placement, naming, and backward compatibility. Recommend specific changes: [paste contract].
Design an additive migration from [current interface] to [target interface]. Identify consumer risks, compatibility steps, deprecation timing, and verification checks.
Design an idempotent workflow for [operation]. Cover key derivation, unique storage, request hashing, concurrent duplicates, unknown outcomes, retention, and failure recovery.
Author
addyosmaniLicense
MIT
Skillstore revision
r2
Version notice
The author did not declare a version.
Ref
5d5054f8a23586f9b500fece1cb613a9dffc787b
Maintenance freshness
9/19/2026
Usage
0 downloads · 0 views
File structure
📄 SKILL.md
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