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/fellipeutaka/leon/tanstack-dbnpx skills add fellipeutaka/leon --skill tanstack-dbgit clone --depth 1 https://github.com/fellipeutaka/leonWhat 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 | $0.00050 | $0.00494 |
| Opus 5 | $0.00025 | $0.00247 |
| Sonnet 5 | $0.00010 | $0.00099 |
| Haiku 4.5 | $0.00005 | $0.00049 |
Grade A, and why
tanstack-db 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.
What it actually says
TanStack DB (React)
Quick Start
TanStack DB is a local-first database and reactivity layer. For React applications, it provides useLiveQuery and optimistic mutations with sub-millisecond updates powered by d2ts.
Core Guidelines
- Schemas Validate Client State: Schemas are StandardSchema-compatible (Zod, Valibot, etc.). They validate client mutations, not server data.
TInputmust be a superset ofTOutputfor updates to work correctly. - Dependency Arrays: All query hooks require dependency arrays as the last argument, identical to
useEffect. Include all external values. Omit to run on every render, or use[]for static queries. - Conditional Queries: To disable a query, return
undefinedornullfrom the callback. - Router Preloading: Preload data in your route loader (
await collection.preload()), then consume it withuseLiveQueryin the component.
Advanced Topics
For deep dives into specific areas, consult the following references:
- Collections & Schemas: See references/core-concepts.md for collection types, sync modes (eager, on-demand, progressive), and schema constraints.
- Queries & Hooks: See references/live-queries.md for the fluent SQL-like API, expression functions,
useLiveSuspenseQuery, and query composition patterns. - Mutations & Transactions: See references/mutations.md for optimistic updates, mutation merging, temporary ID handling, and direct
QueryCollectionwrites. - Error Handling: See references/error-handling.md for specific error types (e.g.,
DuplicateKeyError,SchemaValidationError) and transaction states. - Community Integrations: See references/community-integrations.md for Dexie.js (IndexedDB) and PGLite (WASM PostgreSQL + Drizzle ORM) adapters.
What ships with it
6 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.
- 2d ago First seen · 27 lines · 50 tokens per session scan A 932ba091e626
tanstack-db is a skill published in the GitHub repository fellipeutaka/leon (5 stars, last pushed 4d ago), licensed MIT. It adds 50 tokens to every session and 494 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.
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