gencc-link: Skill for Claude Code

.claude/skills/data-schema-change/SKILL.md

data-schema-change is a skill for Claude Code from berntpopp/gencc-link. It costs 40 tokens per session (733 once invoked), scanned A, original, MIT.

A workflow for changing the schema of a GenCC SQLite database. A schema is the database’s structure, including its tables, columns, indexes, and search settings.

In plain words
What is it for?
Use it when changing GenCC tables, columns, indexes, full-text search, or the aggregated gene-disease data.
Why use it?
It keeps the schema, the code that rebuilds the database, the query layer, tests, and sample data aligned so changes do not break queries.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is berntpopp/gencc-link's own configuration. It tells Claude Code how to work on gencc-link itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything gencc-link configures →

Reuse

Borrowing it

Nothing to install: this file belongs to berntpopp/gencc-link. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/berntpopp/gencc-link/main/.claude/skills/data-schema-change/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/berntpopp/gencc-link

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 data-schema-change

README.md
[![agentmods](https://agentmods.dev/badge/skills/berntpopp/gencc-link/data-schema-change.svg)](https://agentmods.dev/skills/berntpopp/gencc-link/data-schema-change)
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<a href="https://agentmods.dev/skills/berntpopp/gencc-link/data-schema-change"><img src="https://agentmods.dev/badge/skills/berntpopp/gencc-link/data-schema-change.svg" alt="Measured on agentmods" height="20"></a>
Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 733 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original 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 $0.00040 $0.00733
Opus 5 $0.00020 $0.00367
Sonnet 5 $0.00008 $0.00147
Haiku 4.5 $0.00004 $0.00073

Measured 6d ago against content hash af1dbdcd2e11, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

data-schema-change 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 6d 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/skills/data-schema-change/SKILL.md · 60 lines

How it starts

The opening of the file, as written. The whole thing — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Data schema change

Use this skill when changing the shape of the local SQLite store — columns, tables, indexes, FTS5 config, or the aggregated gene_disease roll-up. These three layers must change together or queries will break at runtime.

The three coupled layers

  1. gencc_link/data/schema.sql — the DDL: submissions, genes, diseases, submitters, the aggregated gene_disease table, the genes_fts / diseases_fts FTS5 indexes, and the single-row meta table.
  2. gencc_link/ingest/ — the builder that populates the schema:
    • parser.py parses the 31-column TSV (header validated against the column order in gencc_link/constants.py);
    • aggregates.py computes per-gene / per-disease / per-submitter and per-(gene, disease) roll-ups, including consensus and conflict;
    • builder.py writes rows + aggregates + FTS, sets the meta row, and does the atomic rename.
  3. gencc_link/data/repository.py (+ queries.py) — the read-only query layer that selects from those tables. Every changed column/table must be reflected in the SQL here.

Checklist

  1. Bump the schema version. If the change is not backward compatible with an existing built database, bump SCHEMA_VERSION in gencc_link/constants.py so stale databases are detected.

  2. Edit schema.sql. Add/alter the table, column, index, or FTS definition. Keep FTS5 columns and tokenizer consistent with the search queries.

  3. Update the ingest builder. Adjust parser.py (if the source columns changed — also update SUBMISSION_COLUMNS in constants.py), aggregates.py (if a derived/aggregated value changed — consensus and conflict logic lives in gencc_link/services/consensus.py and is applied at build time), and builder.py (the INSERT/index/FTS population).

  4. Update the repository. Edit repository.py / queries.py so reads match the new schema. Update the service layer (gencc_link/services/) and any Pydantic records (gencc_link/models/records.py) consuming the new fields.

Read the full file on GitHub · 60 lines

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. 6d ago First seen · 60 lines · 40 tokens per session scan A af1dbdcd2e11

Subscribe to this mod's changes

data-schema-change is a skill published in the GitHub repository berntpopp/gencc-link (0 stars, last pushed 3d ago), licensed MIT. It adds 40 tokens to every session and 733 once invoked, about $0.0002 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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