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-specifications-csharpgit 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-specifications-csharp)<a href="https://agentmods.dev/skills/cratis/ai/cratis-specifications-csharp"><img src="https://agentmods.dev/badge/skills/cratis/ai/cratis-specifications-csharp.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 | $0.00098 | $0.02371 |
| Opus 5 | $0.00049 | $0.01185 |
| Sonnet 5 | $0.00020 | $0.00474 |
| Haiku 4.5 | $0.00010 | $0.00237 |
Grade A, and why
cratis-specifications-csharp 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 yesterday.
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 — 231 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Cratis C# specifications
Specifications are executable documentation. The folder tree reads like a table of contents, and each file states one setup, one action, and one or more focused assertions.
Verified product sources
This skill is verified against these exact public releases:
| Package | Version | Purpose |
|---|---|---|
Cratis.Specifications |
4.1.0 |
Specification base, Catch.Exception, ShouldXxx assertions |
Cratis.Arc.Testing |
22.10.4 |
CommandScenario<TCommand> and CommandResult assertions |
Cratis.Chronicle.Testing |
17.0.0 |
EventScenario, ReadModelScenario<T>, ReactorScenario<T> |
Reverify against the owning product repository before claiming support for another version. Never translate an assertion or helper name from memory.
Route near misses
- The specification is TypeScript, React, or a view model: use
cratis-specifications-typescriptinstead. - The question is what a command, projection, reducer, or reactor should do: resolve the behavior first; this skill only specifies already decided behavior.
- The repository builds a Cratis library rather than an application: stay on the
plain
Specificationbase in this file and do not reach for the scenario family except to test the very engine that repository provides.
Step 1 — Choose the specification surface
| Situation | Surface |
|---|---|
| Isolated class, collaborators can be substituted | Specification + NSubstitute |
Arc command pipeline (validators, Provide(), Handle(), appended events) |
CommandScenario<TCommand> |
| Chronicle append semantics, constraints, concurrency | EventScenario |
| Projection or reducer state from a sequence of events | ReadModelScenario<TReadModel> |
| Reactor invocation and its side effects | ReactorScenario<TReactor> |
| Host, transport, or real-infrastructure boundary | Out-of-process Chronicle integration specification |
| Setup shared by many specifications | Reusable context under given/ |
What ships with it
4 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.
- yesterday First seen · 231 lines · 98 tokens per session scan A 8bb2ae277242
cratis-specifications-csharp is a skill published in the GitHub repository Cratis/AI (2 stars, last pushed yesterday), licensed MIT. It adds 98 tokens to every session and 2,371 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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