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 saajunaid/caddis-plugin --skill schema-migrationgit clone --depth 1 https://github.com/saajunaid/caddis-pluginWrote 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/saajunaid/caddis-plugin/schema-migration)<a href="https://agentmods.dev/skills/saajunaid/caddis-plugin/schema-migration"><img src="https://agentmods.dev/badge/skills/saajunaid/caddis-plugin/schema-migration/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/saajunaid/caddis-plugin/schema-migration"><img src="https://agentmods.dev/badge/skills/saajunaid/caddis-plugin/schema-migration.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 | $0.00040 | $0.02339 |
| Opus 5.5 | $0.00016 | $0.00936 |
| Sonnet 5.5 | $0.00008 | $0.00468 |
| Haiku 4.5 | $0.00004 | $0.00234 |
Grade A, and why
schema-migration 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 17d 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 — 276 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Schema Migration Skill
Systematically migrate an application from a legacy database schema to a new schema with zero data loss and full functional parity.
When to Use
- Tables are being renamed, consolidated, or split
- Columns are renamed, retyped, or moved between tables
- The DB team has restructured tables and the app must follow
- Data previously in file storage has been migrated into database tables
- Query files, column mappings, or config need updating after a schema change
- User says "migrate to new tables", "schema changed", or "tables restructured"
Constraints (Read Before Starting)
- Read-Only — Never execute DDL or DML (
CREATE,ALTER,INSERT,UPDATE,DELETE) against the database. All analysis is SELECT-only. - No SQL Aliases — Proposed queries must use direct
Table.Columnnotation. Aliases obscure the mapping and make future changes harder to trace. - No Assumptions — Every column mapping must be verified against the actual schema DDL. If a mapping is ambiguous or a source column has no clear target, flag it as a GAP rather than guessing.
- Scratchpad Protocol — If context becomes large, save intermediate findings to
.caddis/plans/temp_migration_scratchpad.mdto preserve state across reasoning steps.
Phase 1: Schema Forensics
Objective
Build a complete picture of old and new schemas. Produce the Schema Manifest — the single source of truth for the migration.
Actions
-
Collect Legacy Schema DDL
- Extract
CREATE TABLEstatements for all legacy tables (from schema files, INFORMATION_SCHEMA, or DDL scripts) - Note all columns, data types, nullability, defaults, and foreign keys
- Document the table-to-variable mapping (e.g.,
.enventries, config files)
- Extract
-
Collect Target Schema DDL
- Extract
CREATE TABLEstatements for all new/consolidated tables - Note structural differences: merged tables, renamed columns, new columns, removed columns, type changes
- Extract
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.
- 17d ago Changed · -16 tokens per session 0aed4d511ed5
- 1mo ago First seen · 276 lines · 56 tokens per session scan A e6f973aa97c0
schema-migration is a skill published in the GitHub repository saajunaid/caddis-plugin (0 stars, last pushed today), licensed MIT. It adds 40 tokens to every session and 2,339 once invoked, about $0.0002 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 2026-09-03.
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