openai-api

A guide to building applications that use the OpenAI API, the service for adding OpenAI models to software, agents, command-line tools, and workflows.

In plain words
What is it for?
Use it to add model calls, choose models, build tool-using or coding workflows, stream responses, validate structured output, manage keys, or update older Chat Completions code.
Why use it?
It helps avoid outdated integration patterns and makes model choice, streaming, structured results, retries, rate limits, and API-key handling explicit.

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/kid-sid/codex-spellbook/openai-api
Any agent
npx skills add kid-sid/codex-spellbook --skill openai-api
Clone the repo
git clone --depth 1 https://github.com/kid-sid/codex-spellbook

Made for: Claude Code, Codex.

Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,295 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 $0.00056 $0.01295
Opus 5 $0.00028 $0.00647
Sonnet 5 $0.00011 $0.00259
Haiku 4.5 $0.00006 $0.00129

Measured 3d ago against content hash 5732b7d59b4d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

openai-api 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 3d 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/openai-api/SKILL.md · 168 lines

How it starts

The opening of the file, as written. The whole thing — 168 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OpenAI API

Use the OpenAI API through the Responses API by default, choose models intentionally, and keep integration code explicit about validation, retries, and cost boundaries.

When to Activate

  • Add OpenAI API calls to an application or service
  • Choose a model for coding, agentic, or general reasoning work
  • Build a Codex-like coding workflow against the API
  • Implement streaming or tool-calling behavior
  • Add structured outputs or schema validation
  • Review API key handling, retries, or rate-limit behavior
  • Refactor an older Chat Completions integration to a newer pattern

Model Selection

As of April 18, 2026, current official docs indicate:

  • gpt-5.4 is the flagship general model for complex reasoning and coding.
  • gpt-5.4-mini is the lower-latency lower-cost GPT-5.4 variant.
  • gpt-5.3-codex is the current most capable agentic coding model for Codex-like environments.
  • codex-mini-latest is optimized for the Codex CLI; the docs recommend starting with gpt-4.1 for direct general API use of that class.

Sources:

Need Start With Notes
General app logic, strong reasoning, coding gpt-5.4 Best default when quality matters most
Lower latency or cheaper general workloads gpt-5.4-mini Good cost/perf default
Agentic coding in Codex-like workflows gpt-5.3-codex Supports reasoning effort settings
Codex CLI tuning reference codex-mini-latest CLI-oriented, not the default general API pick

API Surface

Situation Preferred Avoid
New integrations Responses API Starting new work on legacy patterns by default
Need multimodal, tools, or stateful interaction Responses API Rebuilding these features manually
Existing stable legacy integration Migrate deliberately Blind rewrites with no regression plan

Read the full file on GitHub · 168 lines

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. 3d ago First seen · 168 lines · 56 tokens per session scan A 5732b7d59b4d

Subscribe to this mod's changes

openai-api is a skill published in the GitHub repository kid-sid/codex-spellbook (21 stars, last pushed 3mo ago), licensed MIT. It adds 56 tokens to every session and 1,295 once invoked, about $0.0003 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 2026-08-30.

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