cratis-chronicle-event-constraints SKILL.md skillA
cratis-chronicle-event-constraints 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-chronicle-event-constraints@git:20261016.b081bc9Pins git:20261016.b081bc9 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-chronicle-event-constraints/SKILL.md- Versions recorded
- 5
- Latest version
- git:20261016.b081bc9, committed Oct 16, 2026
- First version recorded
- Oct 13, 2026
- Size
- 16,240 bytes
- Repository stars
- 4
- License
- MIT
Enforce append-time uniqueness in Chronicle with the [Unique] attribute, [RemoveConstraint], and IConstraint, and specify the violation with EventScenario. Use when a rule must hold at the event store rather than in a command, so two concurrent appends cannot both win. Do not use for ordinary command input validation and do not use to create a projection.
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
# Chronicle event constraints A constraint is an **append-time** invariant. Chronicle evaluates it inside the append, against the event store's own index — so it is the only mechanism that holds when two requests race. A command-side pre-check reads state that may already be stale by the time the append lands; a constraint cannot be. Constraints are discovered automatically. There is no registration call. A constraint binds **every** writer, whichever client or service appends, so it is the mechanism for uniqueness and create-once. It cannot count, sum or test a predicate: capacity and stock rules need a guarded read (read protection `On`), a stream decision or an aggregate. Read [choosing how a rule holds](../cratis-chronicle-decision-reads/references/choosing-how-a-rule-holds.md) when it is unclear which one a rule needs. Limits: the claim is settled after the durable append, so a failed index update can let a later duplicate through until a reindex; constraints apply per event store namespace and event sequence, so tenants in different namespaces can claim the same value; and a constraint is not re-run when the kernel retries a duplicate sequence number. …
Read the whole file at its exact version.
How to install
mdr add cratis/ai/cratis-chronicle-event-constraints@sha256:e7e6cf1f76b5260cThe line at the top of this page pins the label git:20261016.b081bc9, 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_uhdmfijj2vgq36cy)
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Versions
The registry has recorded 5 versions of this file, between Oct 13, 2026 and Oct 16, 2026, more than one a day.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261016.b081bc9 latest | 2026-10-16 | b081bc9 | 16,240 B | A | view · diff |
| git:20261014.8b817dc | 2026-10-14 | 8b817dc | 16,189 B | A | view · diff |
| git:20261014.97fa750 | 2026-10-14 | 97fa750 | 16,135 B | A | view · diff |
| git:20261014.64fcc06 | 2026-10-14 | 64fcc06 | 16,462 B | A | view · diff |
| git:20261013.9c1bacb | 2026-10-13 | 9c1bacb | 16,214 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 (16240 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_uhdmfijj2vgq36cy GET https://markdownregistry.com/api/v1/resolve?ref=cratis/ai/cratis-chronicle-event-constraints GET https://markdownregistry.com/api/v1/blob/e7e6cf1f76b5260cb7f0b7c1354a5bab5b1c3d6cda6976a182a0f66b5a8fecae
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.