cratis-arc-command-validation SKILL.md skillA
cratis-arc-command-validation from cratis/ai is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add cratis/ai/cratis-arc-command-validation@git:20261013.ac5da4ePins git:20261013.ac5da4e in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- cratis/ai
- Path
.cratis/ai/skills/cratis-arc-command-validation/SKILL.md- Versions recorded
- 5
- Latest version
- git:20261013.ac5da4e, committed Oct 13, 2026
- First version recorded
- Oct 7, 2026
- Size
- 15,644 bytes
- Repository stars
- 4
- License
- MIT
Add a rejection rule to an existing Arc command — choosing between ConceptValidator, CommandValidator, a short-circuiting Provide, and a read-model-injected Handle returning a Result of either the event or a ValidationResult. Use when a command must refuse work under some condition. Do not use to define a new command, and do not use for append-time Chronicle constraints.
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
# Arc command validation Every rejection a command can produce has exactly one right home. Putting a rule in the wrong one is not a style problem: a value invariant written per-command stops travelling with the value, and a state-dependent rule written in a validator loses the race it exists to win. **Never throw for a normal business rejection.** An exception out of `Provide()` or `Handle()` is caught by the pipeline and merged as `HasExceptions`, which the HTTP layer maps to **500** — not a validation result. Recoverable, user-facing rejections are validation. (The one exception: an exception type implementing `IValidationFailure` is converted to a validation failure and returns 400. Arc uses that for its own dependency-resolution failures; do not build application rejection on it.) ## Verified product sources | Package | Version | Purpose | | --- | --- | --- | | `Cratis.Arc.Core` | `22.75.0` | `CommandValidator<T>`, `ConceptValidator<T>`, `ValidationResult`, `CommandResult`, the command pipeline, `ARC0004`–`ARC0013` | | `Cratis.Fundamentals` | `7.23.0` | `Cratis.Monads.Result<TResult, TError>` | …
Read the whole file at its exact version.
How to install
mdr add cratis/ai/cratis-arc-command-validation@sha256:4df8cc7f41e60292The line at the top of this page pins the label git:20261013.ac5da4e, 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_aetzmn4ftvqfiwed)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 5 versions of this file, between Oct 7, 2026 and Oct 13, 2026, about one every 2 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261013.ac5da4e latest | 2026-10-13 | ac5da4e | 15,644 B | A | view · diff |
| git:20261012.81f7c14 | 2026-10-12 | 81f7c14 | 14,604 B | A | view · diff |
| git:20261012.1578108 | 2026-10-12 | 1578108 | 14,345 B | A | view · diff |
| git:20261008.86f1c68 | 2026-10-08 | 86f1c68 | 12,908 B | A | view · diff |
| git:20261007.41fab73 | 2026-10-07 | 41fab73 | 12,890 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 (15644 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
cratis/ai · 4 stars · license MIT · pushed 2026-11-04 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_aetzmn4ftvqfiwed GET https://markdownregistry.com/api/v1/resolve?ref=cratis/ai/cratis-arc-command-validation GET https://markdownregistry.com/api/v1/blob/4df8cc7f41e60292eb97e59b6032da4141e2972939879f15836ae69d3afdac22
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.