Borrowing it
Nothing to install: this file belongs to Cratis/VerticalSlices. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/Cratis/VerticalSlices/main/.ai/skills/multi-tenancy/SKILL.mdgit clone --depth 1 https://github.com/Cratis/VerticalSlicesWrote 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/verticalslices/multi-tenancy)<a href="https://agentmods.dev/skills/cratis/verticalslices/multi-tenancy"><img src="https://agentmods.dev/badge/skills/cratis/verticalslices/multi-tenancy/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/verticalslices/multi-tenancy"><img src="https://agentmods.dev/badge/skills/cratis/verticalslices/multi-tenancy.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 | $0.00072 | $0.00637 |
| Opus 5.5 | $0.00029 | $0.00255 |
| Sonnet 5.5 | $0.00014 | $0.00127 |
| Haiku 4.5 | $0.00007 | $0.00064 |
Grade A, and why
multi-tenancy 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 1mo 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.
This is a copy
100% identical to multi-tenancy — 22 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 53 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Multi-Tenancy with Chronicle Namespaces
Chronicle implements multi-tenancy through namespaces: each namespace is a logically separate event store. Events, projections, reducers, and observers run independently per namespace — there is no cross-namespace leakage. Not every Cratis app is multi-tenant — adopt this only when one deployment must serve multiple tenants with isolation.
Core concept
| Term | Meaning |
|---|---|
| Namespace | a named isolation boundary in Chronicle (its own event store) |
| Default namespace | "Default" — used when none is resolved |
All appends, projections, and observers are scoped to the resolved namespace. A reactor for <Entity>Created fires once per tenant namespace that has that event — independently.
Arc tenancy integration
When using Arc with Chronicle, tenancy maps to namespaces automatically: Arc's TenantNamespaceResolver maps the current tenant id to the Chronicle namespace and falls back to the default namespace when no tenant is set. Enable Arc tenancy in startup so the tenant context resolves before each command/query handler runs; namespace wiring is then automatic — no manual resolver registration needed.
If you need custom namespace resolution outside Arc tenancy (header, subdomain, JWT claim), Chronicle supports namespace resolvers registered in priority order; the first non-null result wins, else the default namespace is used.
Observer and reactor isolation
Observers (projections, reducers, reactors) are instantiated per namespace. Consequences:
- A
[OnceOnly]reactor fires once per event source within each namespace (i.e. once per tenant), not globally once — see reactors.md. - Projection rewind affects only the target namespace.
- Each namespace has its own sequence numbers.
Common pitfalls
| Pitfall | Why |
|---|---|
| Storing a tenant id on every event type | the namespace is the tenant — events don't need a tenant property |
| No tenant resolution in a multi-tenant deployment | every tenant lands in "Default" — no isolation |
| Reading one namespace and writing another in the same request | accidental cross-namespace access is a bug (intentional bridging is a Translation reactor) |
Expecting [OnceOnly] to be globally once |
it is per-namespace |
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.
- 1mo ago First seen · 53 lines · 72 tokens per session scan A d88b6633208c
multi-tenancy is a skill published in the GitHub repository Cratis/VerticalSlices (2 stars, last pushed 1mo ago), licensed MIT. It adds 72 tokens to every session and 637 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to multi-tenancy, differing in 22 lines, and is treated as a copy.
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