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 Hainrixz/claude-db --skill db-constraintsgit clone --depth 1 https://github.com/Hainrixz/claude-dbWrote 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/hainrixz/claude-db/db-constraints)<a href="https://agentmods.dev/skills/hainrixz/claude-db/db-constraints"><img src="https://agentmods.dev/badge/skills/hainrixz/claude-db/db-constraints/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/hainrixz/claude-db/db-constraints"><img src="https://agentmods.dev/badge/skills/hainrixz/claude-db/db-constraints.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 | $0.00059 | $0.01162 |
| Opus 5 | $0.00030 | $0.00581 |
| Sonnet 5 | $0.00012 | $0.00232 |
| Haiku 4.5 | $0.00006 | $0.00116 |
Grade A, and why
db-constraints 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 9d 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 — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.
db-constraints (M5)
Constraints are invariants the database guarantees no matter which app, script, or migration writes the row. Without them, "this is always true" is a hope, not a fact. This module is design-axis (Constraints category). It applies to engines that enforce declarative constraints; document stores route to the Validación-schema category instead.
What it checks
- Missing NOT NULL: columns that are semantically required (FKs to mandatory parents,
email,status, timestamps) left nullable, allowing partial/garbage rows. - Missing CHECK: domain rules not enforced —
quantity >= 0,price >= 0,status IN (...),start_date <= end_date,email ~ '@'. The app "validates" it; the DB does not. - Missing UNIQUE: natural keys (email, username, slug, external_id) with no UNIQUE constraint, permitting duplicates that corrupt joins and auth.
- Case-insensitive uniqueness (emails): a plain
UNIQUEon a case-varying column (e.g.email) still admits[email protected]and[email protected]as distinct rows — duplicate identities. Name the remedy: acitextcolumn type, or aUNIQUEexpression index onlower(col)(e.g.CREATE UNIQUE INDEX ON users (lower(email))), so case-folded values collide. - Over-nullable UNIQUE trap: a UNIQUE constraint over nullable columns where the engine treats each NULL as distinct, so duplicates slip through (e.g.
UNIQUE(user_id, deleted_at)for soft-delete uniqueness fails whendeleted_atis NULL). Recommend a partial/filtered unique index orNULLS NOT DISTINCT. - Constraint declared NOT VALID / NOCHECK and never validated.
Axis & severity
- Axis: design; magnitude banded, never a fabricated violation count.
- Missing UNIQUE on an auth/natural key allowing duplicate identities: severity 4,
fail/warn, confidencedirectional. - Over-nullable UNIQUE that silently permits dupes: severity 4,
warn(subtle, high-impact). - Missing NOT NULL on a required FK/column: severity 3,
warn. - Missing CHECK for a stated domain rule: severity 2–3,
warn,fixable: proposed. - M5 does not hold a sev-5 cap; it shapes the Constraints category value.
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.
- 9d ago First seen · 61 lines · 59 tokens per session scan A f8818c0631f0
db-constraints is a skill published in the GitHub repository Hainrixz/claude-db (19 stars, last pushed 2mo ago), licensed MIT. It adds 59 tokens to every session and 1,162 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 2026-08-30.
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