orbital-express: Skill for Claude Code

.claude/skills/add-error-code/SKILL.md

add-error-code is a skill for Claude Code from Hackbyrd/orbital-express. It costs 55 tokens per session (789 once invoked), scanned A, original, MIT.

A workflow for adding a client-facing 4xx error code to a feature and returning it from an action. A 4xx response means the request cannot be accepted because of a client-side problem or business rule.

In plain words
What is it for?
Use it when an API needs to reject a request with a new business-rule error, status code, or client-visible message.
Why use it?
It keeps the error code, translated message, HTTP status, and action behaviour aligned and tested.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is Hackbyrd/orbital-express's own configuration. It tells Claude Code how to work on orbital-express itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything orbital-express configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Hackbyrd/orbital-express. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Hackbyrd/orbital-express/main/.claude/skills/add-error-code/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/Hackbyrd/orbital-express

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for add-error-code

README.md
[![agentmods](https://agentmods.dev/badge/skills/hackbyrd/orbital-express/add-error-code/github.svg)](https://agentmods.dev/skills/hackbyrd/orbital-express/add-error-code)
Your own site
<a href="https://agentmods.dev/skills/hackbyrd/orbital-express/add-error-code"><img src="https://agentmods.dev/badge/skills/hackbyrd/orbital-express/add-error-code/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for add-error-code

Your own site · 80×15
<a href="https://agentmods.dev/skills/hackbyrd/orbital-express/add-error-code"><img src="https://agentmods.dev/badge/skills/hackbyrd/orbital-express/add-error-code.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 789 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00055 $0.00789
Opus 5.5 $0.00022 $0.00316
Sonnet 5.5 $0.00011 $0.00158
Haiku 4.5 $0.00006 $0.00079

Measured 2mo ago against content hash ca645c079ef8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

add-error-code 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 2mo 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.

.claude/skills/add-error-code/SKILL.md · 43 lines

How it starts

The opening of the file, as written. The whole thing — 43 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Add an error code

Error codes live in each feature's error.js, are auto-aggregated into the global ERROR_CODES at startup, and pair with an i18n string. Read README "error.js" and "services/error.js". For the full deep reference, see docs/core/errors.md.

Before editing, include the rejection policy, HTTP status, client-visible message, owning action, and tests in the approved feature plan. Confirm complete structure with yarn repair <Feature> --dry-run, then yarn repair <Feature>; do not manually scaffold a missing error.js.

Shape (in app/<Feature>/error.js, inside LOCAL_ERROR_CODES)

// V1Create            ← group by the action that owns it
<FEATURE>_BAD_REQUEST_INVALID_CREDENTIALS: {
  error: '<FEATURE>.BAD_REQUEST_INVALID_CREDENTIALS', // dot after namespace
  status: 400,
  messages: ['<FEATURE>[invalid_credentials]'] // array of i18n keys
}

Naming (three parts: NAMESPACE _ STATUS _ DESCRIPTION)

  • JS object key: NAMESPACE_STATUS_DESCRIPTION — all caps, underscores throughout (ORDER_BAD_REQUEST_INVALID_STATUS).
  • .error string (sent to client): NAMESPACE.STATUS_DESCRIPTION — a dot after the namespace, underscores elsewhere ('ORDER.BAD_REQUEST_INVALID_STATUS').
  • Status phrasing maps to the code: BAD_REQUEST→400, UNAUTHORIZED→401, NOT_FOUND→404, INTERNAL_SERVER_ERROR→500.
  • Namespace = feature name ALL_CAPS. Truly global codes omit it and live in services/error.js (BAD_REQUEST_INVALID_ARGUMENTS, UNAUTHORIZED, INTERNAL_SERVER_ERROR, SERVICE_UNAVAILABLE).

messages is an array

One conceptual error can carry multiple phrasings; pick one by index at the call site. Default to a single-entry array; you never need the index until a second phrasing exists.

Wire it up

  1. Add the code to app/<Feature>/error.js, grouped under a // V1Action comment.
  2. Add the i18n string(s) to app/<Feature>/languages/en.js (and every other locale) as <FEATURE>[snake_case]; run yarn lang (it validates keys — missing ones throw in test/prod). See add-locale.
  3. Use it in the action:
    return errorResponse(req, ERROR_CODES.<FEATURE>_BAD_REQUEST_X);              // default message (index 0)
    return errorResponse(req, ERROR_CODES.<FEATURE>_BAD_REQUEST_X, 1);           // alternate message by index
    return errorResponse(req, ERROR_CODES.BAD_REQUEST_INVALID_ARGUMENTS, joiErrorsMessage(error)); // custom string (Joi)
    
    In a transaction, use errorResponseRollback(t, req, ERROR_CODES.X) to roll back first. In tasks/socket actions, throw instead of errorResponse.
  4. Add the code to the action's JSDoc Errors: list — and write a test that triggers it and asserts errorResponse(i18n, ERROR_CODES.X). Every documented error code must have a test.
  5. Run yarn conventions:check, focused tests, then yarn test; finish with mandatory review-conventions.

Read the full file on GitHub · 43 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. 2mo ago First seen · 43 lines · 55 tokens per session scan A ca645c079ef8

Subscribe to this mod's changes

add-error-code is a skill published in the GitHub repository Hackbyrd/orbital-express (15 stars, last pushed 2mo ago), licensed MIT. It adds 55 tokens to every session and 789 once invoked, about $0.0002 per session on Opus 5.5. 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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