Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add Cratis/AI --skill cratis-chronicle-event-constraintsgit clone --depth 1 https://github.com/Cratis/AIWrote 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/cratis/ai/cratis-chronicle-event-constraints)<a href="https://agentmods.dev/skills/cratis/ai/cratis-chronicle-event-constraints"><img src="https://agentmods.dev/badge/skills/cratis/ai/cratis-chronicle-event-constraints/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/cratis/ai/cratis-chronicle-event-constraints"><img src="https://agentmods.dev/badge/skills/cratis/ai/cratis-chronicle-event-constraints.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00040 | $0.03782 |
| Opus 5.5 | $0.00016 | $0.01513 |
| Sonnet 5.5 | $0.00008 | $0.00756 |
| Haiku 4.5 | $0.00004 | $0.00378 |
Grade A, and why
cratis-chronicle-event-constraints 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 3d 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 — 314 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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
when it is unclear which one a rule needs.
Requires Chronicle 19.82.2 for constraint-index gap repair.
A failed
post-append index update marks a gap: subsequent governed appends repair the
index from the event log or return ConstraintIndexUnavailable in the result's
error collection without writing. Do not remove the constraint or blindly retry an unknown
append outcome; see append outcomes.
Constraints apply per event store namespace and event sequence, so tenants in
different namespaces can claim the same value. A constraint is not re-run when
the kernel retries a duplicate sequence number.
Verified in the tagged kernel sources listed by append outcomes:
Source/Kernel/Core/EventSequences/EventSequence.AppendSettlement.cs and
EventSequence.Validation.cs.
Verified product sources
| Package | Purpose |
|---|---|
Cratis.Chronicle (client) |
uniqueness, stream closing, constraint builders and append results |
Cratis.Chronicle code analysis |
CHR0017, CHR0018, CHR0020 |
Cratis.Chronicle.Testing |
EventScenario and the IAppendResult Should* assertions |
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 3d ago Changed · -41 tokens per session 6ef9efe5dba5
- 4d ago Changed · +11 lines ea9163e99a7f
- 13d ago Changed e7e6cf1f76b5
- 14d ago Changed · +1 lines 3c4ec802d1fa
- 15d ago Changed · +13 lines 33062a7a1b2c
- 17d ago Changed · +39 lines 5cd9acb081d3
- 23d ago Changed · +15 lines 22e7c5787c32
- 1mo ago Changed · +7 lines ed2ad6d3d821
- 1mo ago First seen · 228 lines · 81 tokens per session scan A a920ee671ba2
cratis-chronicle-event-constraints is a skill published in the GitHub repository Cratis/AI (4 stars, last pushed yesterday), licensed MIT. It adds 40 tokens to every session and 3,782 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 2026-09-08.
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