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.
curl -O https://raw.githubusercontent.com/Hackbyrd/orbital-express/main/.claude/skills/add-error-code/SKILL.mdgit clone --depth 1 https://github.com/Hackbyrd/orbital-expressWrote 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.
[](https://agentmods.dev/skills/hackbyrd/orbital-express/add-error-code)<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.
<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>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once 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 |
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.
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). .errorstring (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
- Add the code to
app/<Feature>/error.js, grouped under a// V1Actioncomment. - Add the i18n string(s) to
app/<Feature>/languages/en.js(and every other locale) as<FEATURE>[snake_case]; runyarn lang(it validates keys — missing ones throw in test/prod). Seeadd-locale. - Use it in the action:
In a transaction, usereturn 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)errorResponseRollback(t, req, ERROR_CODES.X)to roll back first. In tasks/socket actions,throwinstead oferrorResponse. - Add the code to the action's JSDoc
Errors:list — and write a test that triggers it and assertserrorResponse(i18n, ERROR_CODES.X). Every documented error code must have a test. - Run
yarn conventions:check, focused tests, thenyarn test; finish with mandatoryreview-conventions.
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.
- 2mo ago First seen · 43 lines · 55 tokens per session scan A ca645c079ef8
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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