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 agentmods add skills/cratis/ai/add-conceptnpx skills add Cratis/AI --skill add-conceptgit clone --depth 1 https://github.com/Cratis/AIWhat 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 | $0.00065 | $0.00648 |
| Opus 5 | $0.00032 | $0.00324 |
| Sonnet 5 | $0.00013 | $0.00130 |
| Haiku 4.5 | $0.00006 | $0.00065 |
Grade A, and why
add-concept 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 2d 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 — 77 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Add a Cratis concept
This is the legacy repository-local entry point. The canonical package skill is
skills/cratis-fundamentals-concept/SKILL.md; keep behavior aligned until legacy
adapters retire.
Choose the base
- Domain value or non-stream entity ID →
ConceptAs<T>fromCratis.Fundamentals. - Identity actually used as a Chronicle event-source/stream ID →
EventSourceId<T>fromCratis.Chronicle. - Enum → keep the enum.
- DTO-only primitive without domain meaning → keep the primitive.
Both generic bases require an IComparable underlying type.
Value concept
Use a positional record with exactly one wrapped, non-null value. Do not add extra properties; Fundamentals serialization assumes a single-value concept.
public record InvoiceNumber(string Value) : ConceptAs<string>(Value)
{
public static implicit operator InvoiceNumber(string value) => new(value);
}
The reverse primitive → derived conversion is optional. ConceptAs<T> already
provides concept → T. Represent absence with InvoiceNumber?, not a concept
wrapping null.
A NotSet/Empty sentinel is optional domain policy. Add one only when its
backing value is explicitly reserved in the domain.
Chronicle stream identity
public record OrderId(Guid Value) : EventSourceId<Guid>(Value)
{
public static OrderId New() => new(Guid.NewGuid());
public static implicit operator OrderId(Guid value) => new(value);
}
New(), sentinels, and primitive → derived-ID conversions are optional domain
conveniences. Base operators do not construct every derived domain record.
Typed empty/zero values are real specified stream IDs, not
EventSourceId.Unspecified.
Pass the typed ID explicitly to Chronicle append/read operations. Do not add
[Key], [Subject], or [PII] to an EventSourceId<T>-derived member;
Chronicle analyzers CHR0026 and CHR0034 protect those boundaries. Sensitive
natural identifiers use a random surrogate stream ID.
Placement convention
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.
- 2d ago First seen · 77 lines · 65 tokens per session scan A 1edb3be27c98
add-concept is a skill published in the GitHub repository Cratis/AI (2 stars, last pushed 5d ago), licensed MIT. It adds 65 tokens to every session and 648 once invoked, about $0.0003 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 2026-08-31.
Other skills, from other repositories
ship-changes
Ship staged or unstaged local changes: create a branch, make logical commits, push to origin, open a PR with the correct description and label, merge it, close the issues it resolves, and delete the branch locally and on origin. Use whenever the user asks to commit, push, create a PR, ship, or land changes.
add-concept
Use this skill when asked to create a strongly-typed domain identifier or value (such as ProjectId, AuthorName, InvoiceNumber) in a Cratis-based project. Produces a ConceptAs record with the correct conversions and sentinel values.
skill-creator
Create new skills, modify and improve existing skills, and measure skill performance. Use when users want to create a skill from scratch, update or optimize an existing skill, run evals to test a skill, benchmark skill performance with variance analysis, or optimize a skill's description for better triggering accuracy.
cratis-command
Step-by-step guidance for creating a Cratis Arc command — [Command] record, Handle() method, CommandValidator, proxy generation, and React .use() hook with CommandDialog. Use when adding or creating a command, wiring up a form or button to the backend, working with IEventLog, CommandResult, CommandValidator…
cratis-readmodel
Step-by-step guidance for creating a Cratis Chronicle read model from scratch — defining events, choosing between projection and reducer, [ReadModel] record with static query methods, and the generated TypeScript proxy in React. Use when creating a read model, working with [EventType], [ReadModel], IProjectionFor…
add-traces
Use this skill when asked to add OpenTelemetry tracing to a class in a Cratis Chronicle Kernel project. Produces Traces.cs companion files using the [Span] source-generator pattern from Cratis.Traces, registers IActivitySource as a keyed DI service, and injects it into the target class.