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-reactorgit 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-reactor)<a href="https://agentmods.dev/skills/cratis/ai/cratis-chronicle-reactor"><img src="https://agentmods.dev/badge/skills/cratis/ai/cratis-chronicle-reactor.svg" alt="Measured on agentmods" 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 | $0.00091 | $0.03572 |
| Opus 5 | $0.00046 | $0.01786 |
| Sonnet 5 | $0.00018 | $0.00714 |
| Haiku 4.5 | $0.00009 | $0.00357 |
Grade A, and why
cratis-chronicle-reactor 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 today.
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 — 345 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Chronicle reactors
A reactor observes events and does things: calls an external system, or appends follow-up events. A projection or reducer builds state; a reactor causes effects. If the answer is "populate a queryable model", it is not a reactor.
| Need | Use |
|---|---|
| populate a queryable read model from events | a projection |
| a current-state-plus-event transition | a reducer |
| trigger a side effect outside the system | a reactor (automation) |
| append follow-up events elsewhere in the system | a reactor (translation) |
| both a model and an effect | one projection and one reactor |
Verified product sources
This skill is verified against these exact sources:
| Package | Version | Purpose |
|---|---|---|
Cratis.Chronicle |
16.45.2 |
Cratis.Chronicle.Reactors, Cratis.Chronicle.Reactors.SideEffects, Cratis.Chronicle.EventSequences, Cratis.Chronicle.Events |
Cratis.Chronicle.CodeAnalysis |
16.45.2 |
CHR0004, CHR0005, CHR0008, CHR0013, CHR0022, CHR0031, CHR0032 |
Reverify product sources before claiming support for another version.
There is no
ReactorSideEffecttype. It does not exist in Chronicle, in any version. The real return types are listed below; the per-event metadata control it was imagined to provide is whatEventForEventSourceIdactually gives you. Never write it into code or an example.
Write the reactor
using Cratis.Chronicle.Events;
using Cratis.Chronicle.Reactors;
/// <summary>
/// <what this automation does and why>.
/// </summary>
public class <ReactorName>(<IServiceType> <serviceName>) : IReactor
{
/// <summary>Reacts to <see cref="<EventName>"/>.</summary>
public async Task <MethodName>(<EventName> @event, EventContext context) =>
await <serviceName>.<Operation>(@event.<Property>);
}
Cratis.Chronicle.Reactors.IReactor is a marker interface with no members.
Reactors are discovered by that interface — the [Reactor] attribute is optional
and is not what makes a class a reactor. Generic types are not discovered.
What ships with it
1 file 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.
- today First seen · 345 lines · 91 tokens per session scan A c89cee62727c
cratis-chronicle-reactor is a skill published in the GitHub repository Cratis/AI (2 stars, last pushed today), licensed MIT. It adds 91 tokens to every session and 3,572 once invoked, about $0.0005 per session on Opus 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 2026-09-06.
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