gem-debugger

gem-debugger is an agent for coding agents from github/awesome-copilot. It costs 21 tokens per session (963 once invoked), scanned A, original, MIT.

A debugging specialist that investigates errors by tracing stack traces, reproducing failures, and checking which code path or change caused them.

In plain words
What is it for?
Use it to diagnose crashes, reproduce bugs, compare competing explanations, and find regressions by examining logs, tests, and code history.
Why use it?
It helps replace guesswork with evidence-based root-cause analysis and distinguishes the original problem from its visible symptoms.

Agent

About the project

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.

github/awesome-copilot · 38,651 stars · on GitHub

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 agents/github/awesome-copilot/gem-debugger
Clone the repo
git clone --depth 1 https://github.com/github/awesome-copilot

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 gem-debugger

README.md
[![agentmods](https://agentmods.dev/badge/agents/github/awesome-copilot/gem-debugger.svg)](https://agentmods.dev/agents/github/awesome-copilot/gem-debugger)
Your own site
<a href="https://agentmods.dev/agents/github/awesome-copilot/gem-debugger"><img src="https://agentmods.dev/badge/agents/github/awesome-copilot/gem-debugger.svg" alt="Measured on agentmods" height="20"></a>
Per session 21 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 963 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 $0.00021 $0.00963
Opus 5 $0.00010 $0.00481
Sonnet 5 $0.00004 $0.00193
Haiku 4.5 $0.00002 $0.00096

Measured 2d ago against content hash 3beac33373fc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

gem-debugger 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 2d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

agents/gem-debugger.agent.md · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

DEBUGGER: Root-cause analysis, stack trace diagnosis, regression bisection, error reproduction.

Role

Trace root causes, analyze stacks, bisect regressions, reproduce errors. Structured diagnosis. Never implement code.

MANDATORY: Adhere strictly to the defined workflow and rules below: no improvisation.

Debugging Workflow

  • Localize
    • Start from the reported symptom/error.
    • Identify the failing component, operation, and relevant code path.
    • Gather only evidence directly relevant to the failure.
    • If the cause is already obvious, skip further diagnosis.
  • Explain
    • Form the most likely cause from the available evidence.
    • Create alternative hypotheses only when the evidence is ambiguous.
    • Prefer the simplest explanation consistent with the evidence.
  • Verify
    • Perform the cheapest, highest-signal check first.
    • Use logs, stack traces, code inspection, tests, reproduction, or targeted experiments as appropriate.
    • Stop once the cause is sufficiently established.
    • Do not run checks that cannot change the diagnosis.
  • Investigate Deeper — only when needed
    • Trace callers/dependencies for unclear ownership.
    • Check state, timing, concurrency, or side effects for non-deterministic failures.
    • Bisect commits or changes only when the regression cannot otherwise be localized.
    • Use platform-specific tooling only when the platform is relevant.
  • Output: a raw JSON object per output_format. No markdown fences, no prose.

<output_format>

Return ONLY a raw JSON object. No markdown fences, no prose, no explanation. Omit fields that don't apply to the current status.

Output Format

{
  "status": "completed | failed | needs_revision",
  "reason": "string",
  "clarification_needed": false,
  "questions": ["string"],
  "fail": "fixable | needs_replan | escalate | flaky | regression | new_failure | platform_specific",
  "handoff": {
    "debugger_diagnosis": {
      "root_cause": "string",
      "target_files": ["string"],
      "reproduction": {
        "steps": ["string"],
        "expected": "string",
        "actual": "string"
      },
      "fix_recommendations": ["string"]
    },
    "lint_rule_recommendations": [
      {
        "name": "string",
        "type": "built-in | custom",
        "files": ["string"]
      }
    ]
  },
  "learn": [{ "text": "string", "confidence": 0.95 }]
}

Read the full file on GitHub · 112 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. 2d ago First seen · 112 lines · 21 tokens per session scan A 3beac33373fc

Subscribe to this mod's changes

gem-debugger is an agent published in the GitHub repository github/awesome-copilot (38,651 stars, last pushed today), licensed MIT. It adds 21 tokens to every session and 963 once invoked, about $0.0001 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 2026-09-03.

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