error-envelope SKILL.md skillA
error-envelope from sigistry/marketplace is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add sigistry/marketplace/error-envelope@git:20260826.571bc2fPins git:20260826.571bc2f in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- sigistry/marketplace
- Path
plugins/api-contract-keeper/skills/error-envelope/SKILL.md- Versions recorded
- 2
- Latest version
- git:20260826.571bc2f, committed Aug 26, 2026
- First version recorded
- Jul 15, 2026
- Size
- 4,150 bytes
- Repository stars
- 3
- License
- MIT
This skill should be used when the user mentions "error handling", "problem details", "rfc 9457", "rfc 7807", "request validation", "api errors", "zod", "pydantic", "class-validator", "error response format", "problem+json", "validation error", or making an API return consistent, machine-readable errors. It provides the RFC 9457 Problem Details envelope and idiomatic per-stack request-validation patterns.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Error Envelope
## Purpose
Provide one standardized way to (1) validate a request at the boundary and (2) return every error in a consistent, machine-readable envelope. These are high-volume boilerplate that teams re-implement inconsistently, one endpoint returns `{ "error": "bad" }`, the next returns a 200 with `{ "success": false }`, a third leaks a stack trace. The cure is a single validation layer plus a single error format: **RFC 9457 Problem Details** (`application/problem+json`), which obsoletes RFC 7807 (same wire format, updated reference).
## The RFC 9457 envelope
Every error response is `application/problem+json` with these standard members (all optional, but be consistent):
| Member | Meaning |
|---|---|
| `type` | A URI identifying the problem *kind* (dereferenceable docs, or `about:blank`). The primary identifier. |
| `title` | Short, human-readable, stable summary for that `type`. |
| `status` | The HTTP status code, duplicated in the body. |
| `detail` | Human-readable explanation specific to *this* occurrence. |
| `instance` | A URI for this specific occurrence (e.g. the request path or an error id). |
…Read the whole file at its exact version.
How to install
mdr add sigistry/marketplace/error-envelope@sha256:cfe02c34ebd12e03The line at the top of this page pins the label git:20260826.571bc2f, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_rqtn3jbclko7hho6)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between Jul 15, 2026 and Aug 26, 2026, about one every 42 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260826.571bc2f latest | 2026-08-26 | 571bc2f | 4,150 B | A | view · diff |
| git:20260715.6169119 | 2026-07-15 | 6169119 | 4,150 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (4150 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
sigistry/marketplace · 3 stars · license MIT · pushed 2026-10-30 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_rqtn3jbclko7hho6 GET https://markdownregistry.com/api/v1/resolve?ref=sigistry/marketplace/error-envelope GET https://markdownregistry.com/api/v1/blob/cfe02c34ebd12e03db6c7eafebce3a3fb137fd00f57b2c0a4c3ea9bbe2769f28
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.