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 butterbase-ai/butterbase-skills --skill schema-designgit clone --depth 1 https://github.com/butterbase-ai/butterbase-skillsWrote 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/butterbase-ai/butterbase-skills/schema-design)<a href="https://agentmods.dev/skills/butterbase-ai/butterbase-skills/schema-design"><img src="https://agentmods.dev/badge/skills/butterbase-ai/butterbase-skills/schema-design/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/butterbase-ai/butterbase-skills/schema-design"><img src="https://agentmods.dev/badge/skills/butterbase-ai/butterbase-skills/schema-design.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 | $0.00031 | $0.05994 |
| Opus 5.5 | $0.00012 | $0.02398 |
| Sonnet 5.5 | $0.00006 | $0.01199 |
| Haiku 4.5 | $0.00003 | $0.00599 |
Grade A, and why
schema-design 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 18d 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 — 552 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Schema Design Skill
Reference guide for Butterbase's declarative schema DSL. Covers column types, constraints, indexes, and common data modeling patterns.
1. Overview
Butterbase uses a declarative schema DSL — you describe the desired end state of your database, and the platform computes and applies the diff. You never write raw ALTER TABLE or CREATE TABLE SQL. Instead, call manage_schema with action: "apply" and a JSON payload describing your tables, columns, and indexes.
The single manage_schema tool exposes four actions:
| Action | Purpose |
|---|---|
"get" |
Read the current schema |
"dry_run" |
Preview SQL that apply would execute, without running it |
"apply" |
Apply a declarative schema (diffs against current, runs safe DDL) |
"list_migrations" |
List applied migrations, most recent first |
Key principles:
- Idempotent: applying the same schema twice is safe — returns "Schema is up to date" if no changes needed
- Additive by default: new columns and tables are created automatically
- Explicit drops: destructive operations require opt-in via
_drop/_dropColumns - Preview first: use
action: "dry_run"to see what will change before committing - Transactional: each migration runs in a single transaction — all changes commit or all roll back
2. Column Types Reference
| Type | PostgreSQL | Use case |
|---|---|---|
uuid |
UUID | Primary keys, foreign keys |
text |
TEXT | Strings of any length |
integer |
INTEGER | Whole numbers (-2B to 2B) |
bigint |
BIGINT | Large whole numbers |
boolean |
BOOLEAN | True/false flags |
timestamptz |
TIMESTAMPTZ | Dates with timezone |
jsonb |
JSONB | Structured/semi-structured data |
real |
REAL | 32-bit floating point |
double precision |
DOUBLE PRECISION | 64-bit floating point |
vector(N) |
VECTOR(N) | Embeddings (pgvector); e.g. vector(1536) for OpenAI |
Always use
timestamptzinstead oftimestamp.timestampsilently drops timezone info and causes subtle bugs with users in different time zones.
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.
- 18d ago First seen · 552 lines · 31 tokens per session scan A f1217b917e2b
schema-design is a skill published in the GitHub repository butterbase-ai/butterbase-skills (535 stars, last pushed 13d ago), licensed MIT. It adds 31 tokens to every session and 5,994 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-30.
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