What is regression-detector?

A read-only performance regression investigator for a Rust and Android project. It compares current measurements with stored baselines to trace slowdowns, binary growth, and code-size bloat to a commit.

Use it to investigate regressions in Criterion benchmarks, Android macrobenchmarks, shared-library size, and compiled function or crate size.

It helps identify which change caused a measurable performance or binary-size regression without changing the reference baselines. The checks cover microbenchmarks, Android startup measurements, native library size, and bloat.

How po4yka/RIPDPI configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to po4yka/RIPDPI. 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/po4yka/RIPDPI/main/.claude/agents/regression-detector.md

Clone the repo

git clone --depth 1 https://github.com/po4yka/RIPDPI

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.

README.md

[![agentmods](https://agentmods.dev/badge/agents/po4yka/ripdpi/regression-detector/github.svg)](https://agentmods.dev/agents/po4yka/ripdpi/regression-detector)

Your own site

<a href="https://agentmods.dev/agents/po4yka/ripdpi/regression-detector"><img src="https://agentmods.dev/badge/agents/po4yka/ripdpi/regression-detector/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.

Your own site · 80×15

<a href="https://agentmods.dev/agents/po4yka/ripdpi/regression-detector"><img src="https://agentmods.dev/badge/agents/po4yka/ripdpi/regression-detector.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 45 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 891 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.

Model	Per session	Once invoked
Fable 5.1	$0.00045	$0.00891
Opus 5.5	$0.00018	$0.00356
Sonnet 5.5	$0.00009	$0.00178
Haiku 4.5	$0.00005	$0.00089

Measured yesterday against content hash ed62b33a8fd3, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

regression-detector 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.

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/regression-detector.md · 63 lines

How it starts

The opening of the file, as written. The whole thing — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a performance regression analyst for the RIPDPI project (native/rust/ workspace).

Regression Types

Type	Baseline file	Check script
Binary size (.so per ABI)	`scripts/ci/native-size-baseline.json`	`scripts/ci/verify_native_sizes.py`
Bloat hotspots (functions/crates)	`scripts/ci/native-bloat-baseline.json`	`scripts/ci/verify_native_bloat.py`
Criterion microbenchmarks	`scripts/ci/rust-bench-baseline.json`	`scripts/ci/check-criterion-regressions.py`
Android macrobenchmarks	`scripts/ci/macrobenchmark-baseline.json`	`scripts/ci/check-macrobenchmark-regressions.py`

Thresholds (from baselines)

Binary size: read per-library and total growth limits from native-size-baseline.json
Bloat: read text/function/crate and new-entry limits from native-bloat-baseline.json
Criterion: max regression 10% (mean_ns comparison)
Macrobenchmarks: cold start 20%, warm start 15% (median and P95)

Comparison Workflow

Run the check script against current build artifacts vs baseline:
- python3 scripts/ci/verify_native_sizes.py (reads app/build/intermediates/merged_native_libs/)
- python3 scripts/ci/verify_native_bloat.py (runs cargo-bloat against android-jni profile)
- python3 scripts/ci/check-criterion-regressions.py (reads native/rust/target/criterion/)
- python3 scripts/ci/check-macrobenchmark-regressions.py (reads benchmark JSON output)
Dump current values with --dump-current flag to see exact numbers.
Compare delta percentages against thresholds to classify pass/regression.

Decision Framework

Legitimate growth: new feature adds proportional size (e.g., new crate dependency adds expected .text). Verify with git log --oneline for the relevant commits.
Regression needing fix: size/time grows without corresponding new functionality, or exceeds thresholds. Common causes: monomorphization bloat, unnecessary generics, accidental debug info, new heavy dependency.
Noise: Criterion results within 5% on CI runners are often noise. Check --warn-only output and re-run if borderline.

Read the full file on GitHub · 63 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.

yesterday First seen · 63 lines · 45 tokens per session scan A ed62b33a8fd3

Subscribe to this mod's changes

regression-detector is an agent published in the GitHub repository po4yka/RIPDPI (85 stars, last pushed yesterday), licensed BSD-3-Clause. It adds 45 tokens to every session and 891 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 2026-11-07.

Analytics and metrics Debugging android android-vpn anti-censorship censorship-circumvention deep-packet-inspection dns-over-https

regression-detector next to 6 agents from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
regression-detectorpo4yka/RIPDPI	Agent	85	yesterday	BSD-3-Clause	A	45	Claude Code
reliability-engineervmobifystudio/app-dev-team	Agent	5	5d ago	MIT	A	62	Claude Code
patch-validatorParesh-Maheshwari/morphe-ai	Agent	194	1mo ago	GPL-3.0	A	36	Claude Code
target-hunterParesh-Maheshwari/morphe-ai	Agent	194	1mo ago	GPL-3.0	A	37	Claude Code
debug-experttienenwu/fables	Agent	4	3mo ago	MIT	A	226	Claude Code
crash-analyzerhyperb1iss/hyperdroid-skill	Agent	53	9mo ago	MIT	A	64	Claude Code
android-gradle-build-performancekrutikJain/android-agent-skills	Agent	14	7mo ago	MIT	A	27	Claude Code

RIPDPI: Agent for Claude Code