regression-testing

A testing procedure for checking assembly-pipeline changes against real Terra submissions. Terra is a platform for running biomedical data workflows, and regression testing compares new results with previous results.

In plain words
What is it for?
Use it to compare old and new Docker-based pipeline runs, pair matching samples, align outputs, and assess equivalence or improvement.
Why use it?
It reveals whether a pipeline change alters results unexpectedly across many representative samples.

Skill for Claude CodeCodex

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 skills/broadinstitute/viral-ngs/regression-testing
Any agent
npx skills add broadinstitute/viral-ngs --skill regression-testing
Clone the repo
git clone --depth 1 https://github.com/broadinstitute/viral-ngs

Made for: Claude Code, Codex.

Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,531 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.01531
Opus 5 $0.00000 $0.00766
Sonnet 5 $0.00000 $0.00306
Haiku 4.5 $0.00000 $0.00153

Measured yesterday against content hash 7765a57f7a7c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

regression-testing 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 yesterday.

The scan reads SKILL.md. This mod also ships 4 executable files (compare_sample_pair.py, discover_pairs.py, generate_report.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.agents/skills/regression-testing/SKILL.md · 168 lines

How it starts

The opening of the file, as written. The whole thing — 168 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Assembly Regression Testing

End-to-end regression testing for assembly pipeline changes against Terra submissions.

When to Use

Use this playbook when a PR makes functional changes to the assembly or variant-calling pipeline (e.g., swapping variant callers, changing alignment parameters, modifying consensus logic). It compares assembly outputs from old vs new code across hundreds of real samples to validate equivalence or improvement.

Prerequisites

  • gcloud CLI -- authenticated with access to Terra workspace GCS buckets
  • mafft -- for pairwise sequence alignment
  • Python with pandas and matplotlib (e.g., a dataviz venv)
  • dsub -- for running VADR batch jobs on GCP (see the dsub-batch-jobs skill)

Workflow

Step 1: Set Up Terra Submissions (Manual)

The user must manually launch Terra submissions with old and new code:

  1. Run the pipeline on a representative dataset using the main branch Docker image
  2. Run the same pipeline on the same dataset using the feature branch Docker image
  3. Note the submission IDs and workspace bucket for both runs

Step 2: Discover Paired Samples

Use discover_pairs.py to find all comparable old/new sample pairs by crawling GCS Cromwell output directories.

python discover_pairs.py \
  --bucket <workspace-bucket-id> \
  --old-sub <old-submission-id> \
  --new-sub <new-submission-id> \
  --output pairs.json

This produces a JSON mapping sample_name -> {old_tsv, new_tsv} for all samples present in both submissions.

Step 3: Compare Assembly Outputs

Use compare_sample_pair.py to compare each sample pair. This script:

  • Downloads assembly_stats TSVs from GCS
  • Compares metrics (coverage, % reference covered, length, etc.)
  • Downloads FASTA assemblies and aligns them with mafft
  • Reports SNPs, indels (events and bp), ambiguity diffs, and terminal extensions
python compare_sample_pair.py \
  --old-tsv <gcs_uri> --new-tsv <gcs_uri> \
  --work-dir ./results/<sample> \
  --output-json ./results/<sample>.json

Read the full file on GitHub · 168 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 168 lines · 0 tokens per session scan A 7765a57f7a7c

Subscribe to this mod's changes

regression-testing is a skill published in the GitHub repository broadinstitute/viral-ngs (197 stars, last pushed 24d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,531 tokens. 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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