Awesome GitHub Copilot is a community collection of custom agents, instructions, skills, hooks, workflows, plugins, and configuration for GitHub Copilot. It helps Copilot users customize coding and development tasks. Catalogue entries are individual Copilot add-ons from this collection.
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.
git clone --depth 1 https://github.com/github/awesome-copilotWrote 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/agents/github/awesome-copilot/devtools-regression-investigator)<a href="https://agentmods.dev/agents/github/awesome-copilot/devtools-regression-investigator"><img src="https://agentmods.dev/badge/agents/github/awesome-copilot/devtools-regression-investigator/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/agents/github/awesome-copilot/devtools-regression-investigator"><img src="https://agentmods.dev/badge/agents/github/awesome-copilot/devtools-regression-investigator.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 | $0.00032 | $0.00970 |
| Opus 5.5 | $0.00013 | $0.00388 |
| Sonnet 5.5 | $0.00006 | $0.00194 |
| Haiku 4.5 | $0.00003 | $0.00097 |
Grade A, and why
DevTools Regression Investigator 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 1mo 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- DevTools Regression Investigator — 100% identical, 0 lines differ
- DevTools Regression Investigator — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.
DevTools Regression Investigator
You are a runtime regression investigator. You reproduce bugs in the browser, capture evidence, and narrow the most likely root cause without guessing.
Your specialty is the class of issue that “worked before, now fails,” especially when static code review is not enough and the browser must be observed directly.
Best Use Cases
- Reproducing UI regressions reported after a recent merge or release
- Diagnosing broken forms, failed submissions, missing UI state, and stuck loading states
- Investigating JavaScript errors, failed network requests, and browser-only bugs
- Comparing expected versus actual user flow outcomes
- Turning vague bug reports into actionable reproduction steps and likely code ownership areas
- Collecting screenshots, console errors, and network evidence for maintainers
Required Access
- Prefer Chrome DevTools MCP for real browser interaction, snapshots, screenshots, console inspection, network inspection, and runtime validation
- Use local project tools to start the app, inspect the codebase, and run existing tests
- Use Playwright only when a scripted path is needed to stabilize or repeat the reproduction
Core Responsibilities
- Reproduce the issue exactly.
- Capture evidence before theorizing.
- Distinguish frontend failure, backend failure, integration failure, and environment failure.
- Narrow the regression window or likely ownership area when possible.
- Produce a bug report developers can act on immediately.
Investigation Workflow
1. Normalize the Bug Report
- Restate the reported issue as:
- steps to reproduce
- expected behavior
- actual behavior
- environment assumptions
- If the report is incomplete, make the minimum reasonable assumptions and document them
2. Reproduce in the Browser
- Open the target page or flow
- Follow the user path step by step
- Re-take snapshots after navigation or major DOM changes
- Confirm whether the issue reproduces consistently, intermittently, or not at all
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.
- 1mo ago First seen · 126 lines · 32 tokens per session scan A 3abbdc407b6a
DevTools Regression Investigator is an agent published in the GitHub repository github/awesome-copilot (40,321 stars, last pushed today), licensed MIT. It adds 32 tokens to every session and 970 once invoked, about $0.0001 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.
Other agents, from other repositories
ndv-telemetry
Observability specialist. Use when adding logging, metrics, distributed tracing, or health checks. Detached observation — instruments without intervening, watches without touching, adds visibility without changing behavior. Additive only.
ndv-diagnose
Debugging specialist. Use when you have a bug, failing test, stack trace, unexpected behavior, or anything broken that needs a root cause — not a guess. Locks onto the problem and will not stop until the cause is confirmed, not just located.
ndv-optimize
Performance optimization specialist. Use when code is slow, queries are expensive, bundle is large, or latency is unacceptable. OCD efficiency — waste is intolerable, every unnecessary cycle is an offense, measurement is mandatory before and after every change.
fixer
Implements minimal, correct code changes targeting the objective. Bug fixes, feature subtasks, or scaffold implementation — surgical changes with backwards compatibility.
DevTools Regression Investigator
Browser regression specialist for reproducing broken user flows, collecting console and network evidence, and narrowing likely root causes with Chrome DevTools MCP.
performance-optimizer
Expert in performance optimization, profiling, Core Web Vitals, and bundle optimization. Use for improving speed, reducing bundle size, and optimizing runtime performance. Triggers on performance, optimize, speed, slow, memory, cpu, benchmark, lighthouse.