@master4n/http-status

The machine-readable HTTP status registry, optimised for AI agents and RAG pipelines.

Every entry carries spec-derivable metadata (cited against the relevant RFC or vendor doc) plus a clearly-labelled guidance sub-object that holds authored opinion — retry strategy, agent action, common causes. Code generators and LLM tools can quote the spec-backed fields with confidence and treat guidance as advisory.

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For AI agents

• Static JSON registry (no install required):
  • https://unpkg.com/@master4n/http-status@2/http-status-registry.json
  • https://cdn.jsdelivr.net/npm/@master4n/http-status@2/http-status-registry.json
• Discovery file: https://unpkg.com/@master4n/http-status@2/llms.txt
• Subpath imports: @master4n/http-status/iana, /cloudflare, /nginx, /utils.
• Schema: see Schema reference below; full TypeScript declarations ship in index.d.ts.

The guidance sub-object on every entry is authored opinion, not spec. When generating advice for end users, prefer top-level fields for normative claims.

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Installation

npm install @master4n/http-status

Zero runtime dependencies. Dual ESM/CommonJS builds. Tree-shakable via per-vendor sub-paths.

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Quickstart

import { IanaStatus, IanaRegistry } from '@master4n/http-status/iana';
import { isRetryable, hasEmptyBody } from '@master4n/http-status/utils';

// Status code constants
IanaStatus.TOO_MANY_REQUESTS;            // 429
IanaStatus.OK;                            // 200

// Full metadata
const meta = IanaRegistry[429];
meta.phrase;                              // "Too Many Requests"
meta.rfc;                                 // "RFC6585"
meta.specUrl;                             // "https://datatracker.ietf.org/doc/html/rfc6585#section-4"
meta.guidance.retryStrategy;              // "respect-retry-after"
meta.guidance.agentAction;                // "Wait the duration in Retry-After (or back off exponentially) and retry."

// Predicates
isRetryable(503);                         // true
hasEmptyBody(204);                        // true

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Tree-shakable sub-paths

Sub-path	What it exports
@master4n/http-status	Everything (types, predicates, all registries, CompleteRegistry).
@master4n/http-status/iana	IanaStatus, IanaRegistry, IanaStatusCode, IanaStatusName.
@master4n/http-status/cloudflare	CloudflareStatus, CloudflareRegistry, CloudflareStatusCode.
@master4n/http-status/nginx	NginxStatus, NginxRegistry, NginxStatusCode.
@master4n/http-status/utils	Pure predicates only (no registry data). For getMetadata, import from the root.
@master4n/http-status/registry.json	The full pre-built JSON registry.

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Predicate cookbook

import {
  isInformational, isSuccess, isRedirection, isClientError, isServerError, isError,
  isRetryable, hasEmptyBody, isCacheable, requiresAuth,
} from '@master4n/http-status/utils';
import { getMetadata } from '@master4n/http-status';

// Retry decision with respect-Retry-After semantics
async function fetchWithRetry(url: string, attempts = 3): Promise<Response> {
  const res = await fetch(url);
  if (res.ok || !isRetryable(res.status) || attempts <= 0) return res;

  const meta = getMetadata(res.status);
  const retryAfter = res.headers.get('Retry-After');
  const delayMs =
    meta?.guidance.retryStrategy === 'respect-retry-after' && retryAfter
      ? Number(retryAfter) * 1000
      : 2 ** (3 - attempts) * 500;

  await new Promise((r) => setTimeout(r, delayMs));
  return fetchWithRetry(url, attempts - 1);
}

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Schema reference

Every entry in every registry conforms to HttpStatusMetadata:

interface HttpStatusMetadata {
  // Spec-derivable, cited against `specUrl`
  code: number;
  phrase: string;
  category: 'Informational' | 'Success' | 'Redirection' | 'Client Error' | 'Server Error' | 'Vendor Extension';
  source: 'IANA' | 'Cloudflare' | 'Nginx';
  rfc: string | null;                     // e.g. "RFC9110"
  specUrl: string;                        // citation URL
  description: string;
  expectsEmptyBody: boolean;              // RFC 9110: body MUST be empty
  cacheability: 'heuristic' | 'uncacheable'; // RFC 9111 §4.2.2 (was `isCacheable` in ≤2.0.0)
  requiresAuth: boolean;
  safeForMethods: HttpMethod[] | 'all';
  relatedHeaders: { name: string; required: boolean; purpose: string }[];
  aliases: string[];
  deprecated: boolean;

  // Authored guidance — NOT spec. Treat as recommendation.
  guidance: {
    isRetryable: boolean;
    retryStrategy: 'never' | 'immediate' | 'exponential-backoff' | 'respect-retry-after';
    agentAction: string;
    commonCauses: string[];
    relatedStatuses: number[];
  };
}

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Coverage

Source	Codes covered	Count
IANA	100–103, 200–208, 226, 300–305, 307, 308, 400–418, 421–426, 428, 429, 431, 451, 500–508, 510, 511	62
Cloudflare	520, 521, 522, 523, 524, 525, 526, 527, 530	9
Nginx	444, 494, 495, 496, 497, 499	6

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Migration from v1

v2.0.0 is a hard break. The v1 HttpStatus class is gone. See CHANGELOG.md for the one-to-one mapping. The new API gives you full metadata in exchange for the rename.

// v1
HttpStatus.OK.value;           // 200
HttpStatus.OK.name;            // 'OK'
HttpStatus.valueOf(200);       // ['OK']

// v2
IanaStatus.OK;                 // 200
IanaRegistry[200].phrase;      // 'OK'
IanaRegistry[200];             // full metadata (RFC, retry strategy, agent action, …)

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License

MIT © Master4Novice