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.
npx skills add ArabelaTso/Skills-4-SE --skill bug-localizationgit clone --depth 1 https://github.com/ArabelaTso/Skills-4-SEWrote 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/skills/arabelatso/skills-4-se/bug-localization)<a href="https://agentmods.dev/skills/arabelatso/skills-4-se/bug-localization"><img src="https://agentmods.dev/badge/skills/arabelatso/skills-4-se/bug-localization/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/skills/arabelatso/skills-4-se/bug-localization"><img src="https://agentmods.dev/badge/skills/arabelatso/skills-4-se/bug-localization.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00077 | $0.04517 |
| Opus 5.5 | $0.00031 | $0.01807 |
| Sonnet 5.5 | $0.00015 | $0.00903 |
| Haiku 4.5 | $0.00008 | $0.00452 |
Grade A, and why
bug-localization 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.
How it starts
The opening of the file, as written. The whole thing — 702 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Bug Localization
Precisely identify the location of bugs in source code by analyzing error messages, stack traces, failing tests, and code patterns. Provides ranked suspect locations with confidence scores and evidence.
Core Capabilities
1. Error Analysis
Extract information from error sources:
- Stack traces - Parse and analyze call stacks
- Error messages - Interpret exception details
- Failing tests - Analyze test failures and assertions
- Crash reports - Process crash dumps and core files
- Log messages - Trace execution through logs
- Debugger output - Interpret breakpoint and watch data
2. Code Analysis
Examine code for bug indicators:
- Data flow - Trace variables and values
- Control flow - Analyze execution paths
- Type mismatches - Detect type-related issues
- Null/undefined access - Find potential null dereferences
- Boundary violations - Detect array/buffer overflows
- Concurrency issues - Identify race conditions
3. Suspect Ranking
Prioritize likely bug locations:
- Confidence scores - Rank suspects by likelihood
- Evidence strength - Quantify supporting evidence
- Historical data - Consider past bug patterns
- Code complexity - Factor in cyclomatic complexity
- Recent changes - Weigh recent modifications
- Code churn - Consider frequently modified code
4. Investigation Guidance
Provide actionable next steps:
- Verification steps - How to confirm the bug
- Debugging strategies - Where to set breakpoints
- Test cases - Tests to reproduce the bug
- Related code - Other potentially affected areas
Bug Localization Workflow
Step 1: Gather Evidence
Collect all available information:
From stack trace:
Traceback (most recent call last):
File "app.py", line 45, in process_order
total = calculate_total(items)
File "billing.py", line 23, in calculate_total
price = item['price'] * item['quantity']
KeyError: 'price'
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 · 702 lines · 77 tokens per session scan A 719e8f6a52c8
bug-localization is a skill published in the GitHub repository ArabelaTso/Skills-4-SE (258 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 77 tokens to every session and 4,517 once invoked, about $0.0003 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 2026-08-30.
Other skills, from other repositories
diagnose
Disciplined diagnosis loop for hard bugs and performance regressions. Reproduce → minimise → hypothesise → instrument → fix → regression-test. Use when user says "diagnose this" / "debug this", reports a bug, says something is broken/throwing/failing, or describes a performance regression.
skill-incident-management
Incident response, postmortem facilitation, root cause analysis (RCA), blameless culture, incident timeline documentation, and incident classification. Use when responding to production incidents, writing incident reports, facilitating postmortems, or improving incident response processes.
triage
Triage issues through a state machine driven by triage roles. Use when user wants to create an issue, triage issues, review incoming bugs or feature requests, prepare issues for an AFK agent, or manage issue workflow.
skill-performance-optimization
Profile systems, identify bottlenecks, optimize code and infrastructure for speed, throughput, and resource efficiency.
skill-code-quality
This skill should be used when implementing code quality standards, setting up linting/testing/security scans, enforcing coverage thresholds, or establishing CI/CD guardrails.
skill-pr-review
Comprehensive code review for pull requests using parallel multi-agent analysis. Audits CLAUDE.md compliance, checks for bugs, analyzes git history, reviews comments, and filters by confidence score. Use when reviewing a GitHub PR, mentions "code review", "review this PR", or "/code-review".