api-integration

A guide for building and connecting APIs, webhooks, HTTP clients, and third-party services. APIs are interfaces that let software exchange requests and data; webhooks let one service notify another when something happens.

In plain words
What is it for?
Use it to design service boundaries, call external APIs, receive webhooks, handle authentication, manage retries and timeouts, and validate data crossing between systems.
Why use it?
It helps prevent common integration failures such as unsafe retries, duplicate webhook handling, missing validation, broken pagination, and unclear error behavior.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/soden46/engineer-flow/api-integration
Any agent
npx skills add soden46/engineer-flow --skill api-integration
Clone the repo
git clone --depth 1 https://github.com/soden46/engineer-flow

Made for: Claude Code, Codex.

Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 259 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00027 $0.00259
Opus 5 $0.00014 $0.00130
Sonnet 5 $0.00005 $0.00052
Haiku 4.5 $0.00003 $0.00026

Measured 2d ago against content hash 0e449dde7042, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api-integration scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/engineer-flow/core/api-integration/SKILL.md · 50 lines

What it actually says

api-integration

Use this skill for APIs, HTTP clients, webhooks, third-party integrations, service communication, pagination, retries, and integration boundaries.

Principles

Define explicit contracts for requests, responses, errors, and side effects.

Validate data crossing external boundaries.

Distinguish transport concerns from business logic.

For outbound calls consider:

  • timeouts
  • retries
  • retry safety
  • idempotency
  • rate limits
  • pagination
  • partial failure
  • authentication
  • observability

Do not retry non-idempotent operations blindly.

For webhooks consider:

  • authenticity
  • replay protection when required
  • duplicate delivery
  • idempotent handling
  • failure recovery

Keep provider-specific assumptions isolated where practical.

Do not leak transport-specific details throughout unrelated application code.

Adaptation

Use project evidence to determine the actual language, framework, runtime, and existing conventions.

When stack-specific implementation guidance is needed, prefer project evidence, native framework or language mechanisms, and relevant user-installed specialist skills. Technology-specific guidance must not redefine or weaken the core engineering requirement.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 50 lines · 27 tokens per session scan A 0e449dde7042

Subscribe to this mod's changes

api-integration is a skill published in the GitHub repository soden46/engineer-flow (3 stars, last pushed 4d ago), licensed MIT. It adds 27 tokens to every session and 259 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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