regression-search

regression-search is a skill for Claude Code, Codex from sonichi/sutando. It costs 47 tokens per session (790 once invoked), scanned A, original, MIT.

A search tool for phone-call transcripts that finds calls related to a feature and shows whether they worked or failed over time. It can also inspect one call for refusals, errors, silence, or repeated requests.

In plain words
What is it for?
Use it to find when a feature stopped working, check whether it later improved, or verify that a bug can still be reproduced before releasing a fix.
Why use it?
It avoids reading more than a hundred transcripts by hand when investigating a feature regression, which is when something that worked before starts failing.

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/sonichi/sutando/regression-search
Any agent
npx skills add sonichi/sutando --skill regression-search
Clone the repo
git clone --depth 1 https://github.com/sonichi/sutando

Made for: Claude Code, Codex.

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 regression-search

README.md
[![agentmods](https://agentmods.dev/badge/skills/sonichi/sutando/regression-search.svg)](https://agentmods.dev/skills/sonichi/sutando/regression-search)
Your own site
<a href="https://agentmods.dev/skills/sonichi/sutando/regression-search"><img src="https://agentmods.dev/badge/skills/sonichi/sutando/regression-search.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 790 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 5.1 $0.00047 $0.00790
Opus 5 $0.00023 $0.00395
Sonnet 5 $0.00009 $0.00158
Haiku 4.5 $0.00005 $0.00079

Measured 5d ago against content hash 26f2e1b77105, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

regression-search 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 5d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/diagnose-call.py, scripts/find-regression.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.

skills/regression-search/SKILL.md · 68 lines

How it starts

The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Two scripts for hunting down bad calls without reading every transcript:

  1. find-regression.py — search results/calls/calls.jsonl for calls touching a feature, classify each as working/broken, print a sorted timeline.
  2. diagnose-call.py — drill into a single call by SID, report refusals/errors/silences/repeated requests, optionally show metrics from data/call-metrics.jsonl.

Closes #188.

When to use

  • "When did the X feature stop working?" — pass the feature keyword.
  • "Has feature Y improved?" — see the broken/working trend over time.
  • Before shipping a fix — sanity check that the regression is reproducible.

Usage

python3 skills/regression-search/scripts/find-regression.py "record"
python3 skills/regression-search/scripts/find-regression.py "summon" --since 2026-04-01
python3 skills/regression-search/scripts/find-regression.py "play" --json

Flags:

  • --since YYYY-MM-DD — only show calls on/after this date
  • --json — machine-readable output
  • --show-snippet — print a one-line transcript snippet for each call

Heuristics

A call is broken for a query if any of:

  • Sutando refuses ("I can't", "I'm not able", "I'm unable", "sorry I cannot")
  • Sutando reports an error ("error", "failed", "didn't work", "something went wrong")
  • The user repeats the same request 2+ times in a row (Sutando didn't respond usefully)
  • Sutando says "(Silence)" after the user mentions the feature

Otherwise the call is working if Sutando's response includes the feature keyword and isn't flagged broken.

These are intentionally crude — the goal is "good enough to find the regression window without reading 163 transcripts." Tune as you find false positives.

Limitations

  • Keyword matching only. "recording doesn't stop" vs "recording won't start" both match record. The issue calls this out as future work.
  • No semantic understanding. A call where Sutando talks about recording but the user wanted something else still matches.
  • Doesn't correlate with git commits — manual step for now.

Read the full file on GitHub · 68 lines

Files

What ships with it

3 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. 5d ago First seen · 68 lines · 47 tokens per session scan A 26f2e1b77105

Subscribe to this mod's changes

regression-search is a skill published in the GitHub repository sonichi/sutando (391 stars, last pushed today), licensed MIT. It adds 47 tokens to every session and 790 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 2026-08-30.