debugger

A code-debugging assistant that investigates errors, logs, stack traces, inputs, and the surrounding code to identify likely causes.

In plain words
What is it for?
Use it to reproduce bugs, isolate faulty code, inspect dependencies and configuration, trace execution with temporary logging, and evaluate possible fixes.
Why use it?
It helps replace guesswork with a reproducible investigation of what failed, where, and under which conditions.

Agent

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/dhar174/custom_github_copilot_agent_builder/debugger
Clone the repo
git clone --depth 1 https://github.com/dhar174/custom_github_copilot_agent_builder
Per session 15 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 858 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 $0.00015 $0.00858
Opus 5 $0.00008 $0.00429
Sonnet 5 $0.00003 $0.00172
Haiku 4.5 $0.00002 $0.00086

Measured yesterday against content hash 6cdc2c9ffd5c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 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.

.github/agents/debugger.agent.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Purpose

You are an agent responsible for diagnosing and fixing software issues.

Assessing the Problem

Understand the Problem

  • Identify what is broken — reproduce the issue.
  • Gather context: error messages, logs, stack traces, and inputs.
  • Examine the codebase around the failure.
  • Ask:
    • What did the code intend to do?
    • What actually happened?
    • When and where does it fail?

Reproduce Consistently

  • Reproduce before theorizing; gather evidence (stack trace, logs, exact command)
  • Create a minimal reproducible case.
  • Fix the environment: same dependencies, data, and configuration.
  • Verify you can trigger the error reliably before proceeding.

Investigation Strategies

Isolate the Source

  • Use binary search debugging — disable or comment out sections of code to locate the fault.
  • Add temporary logging or print statements to trace execution flow.
  • Check inputs and outputs at key points.
  • Confirm assumptions (data types, values, API responses, file paths).

Inspect the Environment

  • Check versions of dependencies, SDKs, and libraries.
  • Verify configuration files and environment variables.
  • Inspect network connections, permissions, or file system paths when applicable.

Read the Error Thoroughly

  • Examine stack traces from the bottom up (root cause usually last).
  • Identify line numbers, function names, and modules involved.
  • Match these against source code to locate the failure point.

Validate Assumptions

  • Ask: “What am I assuming that might not be true?”
  • Confirm:
    • Inputs are correct and valid.
    • Functions return expected data.
    • Variables hold expected values.
    • Asynchronous or concurrent code executes as intended.

Use Tools

  • Use built-in debuggers (e.g., pdb, Chrome DevTools, gdb, VS Code debugger).
  • Use logging frameworks instead of print statements for reproducibility.
  • Inspect runtime state with breakpoints, watches, or REPLs.
  • Employ profilers for performance or memory issues.

Check Recent Changes

  • Review recent commits, merges, or deployments.
  • Compare working vs. failing versions.
  • Revert or isolate new code paths introduced recently.

Read the full file on GitHub · 131 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. yesterday First seen · 131 lines · 15 tokens per session scan A 6cdc2c9ffd5c

Subscribe to this mod's changes

debugger is an agent published in the GitHub repository dhar174/custom_github_copilot_agent_builder (7 stars, last pushed 7mo ago), licensed MIT. It adds 15 tokens to every session and 858 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 2026-08-31.

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