db-migration-guardian

db-migration-guardian is an agent for Claude Code from mantacron/manta. It costs 78 tokens per session (3,156 once invoked), scanned A, original, no licence file.

A database-change safety checker for migration files, which update the structure or rules of stored data.

In plain words
What is it for?
Use it to review migrations written for common database tools and raw SQL, including indexes, NULL rules, rollbacks, and incompatible schema changes.
Why use it?
It identifies changes that could lock large tables, lose data, lack a rollback, or break existing applications before a commit.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

Install

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.

agentmods
npx agentmods add agents/mantacron/manta/db-migration-guardian
Clone the repo
git clone --depth 1 https://github.com/mantacron/manta

Made for: Claude Code.

Wrote 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.

agentmods badge for db-migration-guardian

README.md
[![agentmods](https://agentmods.dev/badge/agents/mantacron/manta/db-migration-guardian.svg)](https://agentmods.dev/agents/mantacron/manta/db-migration-guardian)
Your own site
<a href="https://agentmods.dev/agents/mantacron/manta/db-migration-guardian"><img src="https://agentmods.dev/badge/agents/mantacron/manta/db-migration-guardian.svg" alt="Measured on agentmods" height="20"></a>
Per session 78 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,156 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00078 $0.03156
Opus 5 $0.00039 $0.01578
Sonnet 5 $0.00016 $0.00631
Haiku 4.5 $0.00008 $0.00316

Measured 2d ago against content hash 905afcdae9ab, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

db-migration-guardian 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.

.claude/agents/db-migration-guardian.md · 326 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

Changes

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.

  1. 2d ago Changed · +27 lines 905afcdae9ab
  2. 6d ago First seen · 299 lines · 78 tokens per session scan A 5972f8fa820f

Subscribe to this mod's changes

db-migration-guardian is an agent published in the GitHub repository mantacron/manta (10 stars, last pushed 4d ago), with no licence file. It adds 78 tokens to every session and 3,156 once invoked, about $0.0004 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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