ClaudSkills / Engineering / engineering-misc

API Idempotency Retry

Q: What is a Claude Code skill and how does the API Idempotency Retry skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. API Idempotency Retry is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Engineering category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Engineering · Sub-category: engineering-misc · Last updated: 2026-09-28

Design idempotency-key support and client retry guidance for a public API so integrators retry safely - key derivation and per-caller scoping, storage TTL and replay windows, atomic claim mechanisms (DB unique constraint, SERIALIZABLE row lock, conditional writes), payload-mismatch rejection, in-flight duplicate handling, exponential backoff with jitter, retry budgets, timeout propagation, and SDK retry defaults. Use whenever the user mentions an Idempotency-Key header, duplicate or double-submitted requests, safe POST retries, backoff, or jitter - even if they never say "idempotency". Do NOT use for what the error response signals (samber/developer-platform-skills@api-error-design) or webhook delivery retries (samber/developer-platform-skills@webhook-platform-design).

Security AStatic scan found no risk patternsHow grading works ›

From the source SKILL.md

You design the two halves of one guarantee: server-side idempotency keys that make a retried write safe, and client-side retry behavior that uses them responsibly. Shipping either half alone is the trap - Resilience4j's own docs state it as a hard constraint, not a suggestion: retried operations must be idempotent, so retry guidance without key support (or the reverse) leaves the guarantee open exactly where a dropped connection tests it.

What this skill does

API Idempotency Retry is a community-contributed Claude Code skill in the engineering-misc sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/api-idempotency-retry/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use whenever the user mentions an Idempotency-Key header, duplicate or double-submitted requests, safe POST retries, backoff, or jitter - even if they never say "idempotency". Do NOT use for what the error response signals (samber/developer-platform-skills@api-error-design) or webhook delivery retries (samber/developer-platform-skills@webhook-platform-design).

Who uses this skill

The API Idempotency Retry Claude Code skill is built for software engineers, backend developers, full-stack teams, and technical leads building and maintaining production systems. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 196,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/api-idempotency-retry
curl -L https://claudskills.com/skills/api-idempotency-retry/SKILL.md \
  -o ~/.claude/skills/api-idempotency-retry/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/api-idempotency-retry/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/api-idempotency-retry/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\api-idempotency-retry\SKILL.md on Windows. See the full install guide for step-by-step instructions.

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the API Idempotency Retry Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/api-idempotency-retry/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the API Idempotency Retry skill do?

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

When should I use the API Idempotency Retry skill?

Use API Idempotency Retry when your Claude Code task falls under the Engineering category — specifically in the engineering misc area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use API Idempotency Retry" or describe the task and let Claude pick). Browse related skills at /category/engineering/.

What is a Claude Code skill and how does the API Idempotency Retry skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. API Idempotency Retry is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Engineering category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/samber/developer-platform-skills/blob/HEAD/skills/api-idempotency-retry/SKILL.md
License: MIT
Author: samber

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

samber. (2026). API Idempotency Retry [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/api-idempotency-retry/

BibTeX

@misc{api-idempotency-retry-2026,
  author    = {samber},
  title     = {API Idempotency Retry [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/api-idempotency-retry/}
}

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Badge

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Security scan

Grade A · scanned 2026-09-28 — free static scan against the OWASP Agentic Skills Top 10.

No risk patterns were found in any of the ten OWASP-aligned categories. How grading works ›

✓ Prompt injection
✓ Data exfiltration
✓ Supply chain
✓ Reverse shell
✓ Credentials
✓ Execution
✓ Filesystem
✓ Persistence
✓ Obfuscation
✓ Network

Show this grade on your repo (click to copy):

[![Security: A](https://img.shields.io/badge/Security-A-2e7d32)](https://claudskills.com/skills/api-idempotency-retry/#security)

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Browse all Engineering skills → Top 100 skills

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