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-read-modelgit 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-read-model)<a href="https://agentmods.dev/skills/cratis/ai/cratis-chronicle-read-model"><img src="https://agentmods.dev/badge/skills/cratis/ai/cratis-chronicle-read-model/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-read-model"><img src="https://agentmods.dev/badge/skills/cratis/ai/cratis-chronicle-read-model.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 | $0.00097 | $0.03413 |
| Opus 5.5 | $0.00039 | $0.01365 |
| Sonnet 5.5 | $0.00019 | $0.00683 |
| Haiku 4.5 | $0.00010 | $0.00341 |
Grade A, and why
cratis-chronicle-read-model 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 — 288 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Chronicle read models
A read model is derived state built from events. The path is:
event types -> read-model record -> a projection or a reducer -> a query surface
Chronicle owns the events, the projection or reducer, and the stored instance. The query surface is Arc's, and the two halves are separable: a read model that only exists to be read from inside the backend needs no query surface at all.
Verified product sources
Sources:
| Package | Purpose |
|---|---|
Cratis.Chronicle |
Cratis.Chronicle.Events, Cratis.Chronicle.Keys, Cratis.Chronicle.ReadModels; style and discovery (Source/Clients/DotNET/Reducers/{SelfReducerMethods,RegisteredReducerReadModel}.cs, ReadModels/ReadModelBuilderOwnership.cs, DefaultClientArtifactsProvider.cs) |
Cratis.Arc.Core |
Cratis.Arc.Queries.ModelBound.ReadModelAttribute and PathAttribute |
Cratis.Arc.MongoDB |
the Observe family of IMongoCollection<T> extensions |
Reverify product sources before claiming support for another version. Confirm the exact Arc package version in the consuming project before citing one.
Step 1 — Define the events
Events are the source of truth. Each is a record carrying
Cratis.Chronicle.Events.EventTypeAttribute, named as a past-tense fact.
using Cratis.Chronicle.Events;
/// <summary>Emitted when <description>.</summary>
[EventType]
public record <EntityName><PastTenseVerb>(<ConceptType> <PropertyName>);
- One clear purpose per event; do not mix concerns into one fact.
- Avoid nullable properties. Analyzer
CHR0012warns on them. Model an optional fact as a separate event. - Prefer strongly typed concept properties over raw primitives.
- An event never carries its own event-source id as a payload property — the id is in the event context.
[EventType]takes(string id = "", uint generation = 1). Pass neither for a new event: the id defaults to the CLR type name and the generation to1.
Step 2 — Define the read-model record
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 · +7 lines 01c09da18e5d
- 5d ago Changed · +1 lines aec60664d501
- 6d ago Changed · +1 lines 2dc92867cd2c
- 7d ago Changed · +38 lines 4c0306b40c3c
- 9d ago Changed 1fa362286bd7
- 12d ago Changed · +16 tokens per session 03c92f3c934a
- 15d ago Changed · +13 lines 8a4e5ca2a715
- 17d ago Changed · +34 lines c25f3eb897e8
- 1mo ago Changed c8bb7126c648
- 1mo ago First seen · 194 lines · 81 tokens per session scan A 0f7e675c7a1f
cratis-chronicle-read-model is a skill published in the GitHub repository Cratis/AI (4 stars, last pushed yesterday), licensed MIT. It adds 97 tokens to every session and 3,413 once invoked, about $0.0004 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 2026-09-06.
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