debug-with-file
Improves debugging accuracy by documenting exploration and analyzing logs systematically.
Install
mkdir -p .claude/skills/debug-with-file && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/2368" && unzip -o skill.zip -d .claude/skills/debug-with-file && rm skill.zipInstalls to .claude/skills/debug-with-file
Activation
This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.
Interactive hypothesis-driven debugging with documented exploration, understanding evolution, and analysis-assisted correction.Key capabilities
- →Document exploration in understanding.md
- →Generate testable hypotheses
- →Add NDJSON logging instrumentation
- →Analyze evidence from debug logs
- →Consolidate learning and insights
How it works
The agent maintains a structured session folder containing logs and an evolving understanding document to track hypotheses and evidence.
Inputs & outputs
When to use debug-with-file
- →Debug complex application errors
- →Document root cause analysis
- →Fix persistent bugs systematically
About this skill
Codex Debug-With-File Prompt
Overview
Enhanced evidence-based debugging with documented exploration process. Records understanding evolution, consolidates insights, and uses analysis to correct misunderstandings.
Core workflow: Explore → Document → Log → Analyze → Correct Understanding → Fix → Verify
Key enhancements over /prompts:debug:
- understanding.md: Timeline of exploration and learning
- Analysis-assisted correction: Validates and corrects hypotheses
- Consolidation: Simplifies proven-wrong understanding to avoid clutter
- Learning retention: Preserves what was learned, even from failed attempts
Target Bug
$BUG
Project Context
Run ccw spec load --category debug for known issues, workarounds, and root-cause notes.
Execution Process
Session Detection:
├─ Check if debug session exists for this bug
├─ EXISTS + understanding.md exists → Continue mode
└─ NOT_FOUND → Explore mode
Explore Mode:
├─ Locate error source in codebase
├─ Document initial understanding in understanding.md
├─ Generate testable hypotheses with analysis validation
├─ Add NDJSON logging instrumentation
└─ Output: Hypothesis list + await user reproduction
Analyze Mode:
├─ Parse debug.log, validate each hypothesis
├─ Use analysis to evaluate hypotheses and correct understanding
├─ Update understanding.md with:
│ ├─ New evidence
│ ├─ Corrected misunderstandings (strikethrough + correction)
│ └─ Consolidated current understanding
└─ Decision:
├─ Confirmed → Fix root cause
├─ Inconclusive → Add more logging, iterate
└─ All rejected → Assisted new hypotheses
Fix & Cleanup:
├─ Apply fix based on confirmed hypothesis
├─ User verifies
├─ Document final understanding + lessons learned
├─ Remove debug instrumentation
└─ If not fixed → Return to Analyze mode
Implementation Details
Session Setup & Mode Detection
Step 0: Determine Project Root
检测项目根目录,确保 .workflow/ 产物位置正确:
PROJECT_ROOT=$(git rev-parse --show-toplevel 2>/dev/null || pwd)
优先通过 git 获取仓库根目录;非 git 项目回退到 pwd 取当前绝对路径。
存储为 {projectRoot},后续所有 .workflow/ 路径必须以此为前缀。
const getUtc8ISOString = () => new Date(Date.now() + 8 * 60 * 60 * 1000).toISOString()
const projectRoot = bash('git rev-parse --show-toplevel 2>/dev/null || pwd').trim()
const bugSlug = "$BUG".toLowerCase().replace(/[^a-z0-9]+/g, '-').substring(0, 30)
const dateStr = getUtc8ISOString().substring(0, 10)
const sessionId = `DBG-${dateStr}-${bugSlug}`
const sessionFolder = `${projectRoot}/.workflow/.debug/${sessionId}`
const debugLogPath = `${sessionFolder}/debug.log`
const understandingPath = `${sessionFolder}/understanding.md`
const hypothesesPath = `${sessionFolder}/hypotheses.json`
// Auto-detect mode
const sessionExists = fs.existsSync(sessionFolder)
const hasUnderstanding = sessionExists && fs.existsSync(understandingPath)
const logHasContent = sessionExists && fs.existsSync(debugLogPath) && fs.statSync(debugLogPath).size > 0
const mode = logHasContent ? 'analyze' : (hasUnderstanding ? 'continue' : 'explore')
if (!sessionExists) {
bash(`mkdir -p ${sessionFolder}`)
}
Explore Mode
Step 1.1: Locate Error Source
// Extract keywords from bug description
const keywords = extractErrorKeywords("$BUG")
// Search codebase for error locations
const searchResults = []
for (const keyword of keywords) {
const results = Grep({ pattern: keyword, path: ".", output_mode: "content", "-C": 3 })
searchResults.push({ keyword, results })
}
// Identify affected files and functions
const affectedLocations = analyzeSearchResults(searchResults)
Step 1.2: Document Initial Understanding
Create understanding.md:
# Understanding Document
**Session ID**: ${sessionId}
**Bug Description**: $BUG
**Started**: ${getUtc8ISOString()}
---
## Exploration Timeline
### Iteration 1 - Initial Exploration (${timestamp})
#### Current Understanding
Based on bug description and initial code search:
- Error pattern: ${errorPattern}
- Affected areas: ${affectedLocations.map(l => l.file).join(', ')}
- Initial hypothesis: ${initialThoughts}
#### Evidence from Code Search
${searchResults.map(r => `
**Keyword: "${r.keyword}"**
- Found in: ${r.results.files.join(', ')}
- Key findings: ${r.insights}
`).join('\n')}
#### Next Steps
- Generate testable hypotheses
- Add instrumentation
- Await reproduction
---
## Current Consolidated Understanding
${initialConsolidatedUnderstanding}
Step 1.3: Generate Hypotheses
Analyze the bug and generate 3-5 testable hypotheses:
// Hypothesis generation based on error pattern
const HYPOTHESIS_PATTERNS = {
"not found|missing|undefined|未找到": "data_mismatch",
"0|empty|zero|registered": "logic_error",
"timeout|connection|sync": "integration_issue",
"type|format|parse": "type_mismatch"
}
function generateHypotheses(bugDescription, affectedLocations) {
// Generate targeted hypotheses based on error analysis
// Each hypothesis includes:
// - id: H1, H2, ...
// - description: What might be wrong
// - testable_condition: What to log
// - logging_point: Where to add instrumentation
// - evidence_criteria: What confirms/rejects it
return hypotheses
}
Save to hypotheses.json:
{
"iteration": 1,
"timestamp": "2025-01-21T10:00:00+08:00",
"hypotheses": [
{
"id": "H1",
"description": "Data structure mismatch - expected key not present",
"testable_condition": "Check if target key exists in dict",
"logging_point": "file.py:func:42",
"evidence_criteria": {
"confirm": "data shows missing key",
"reject": "key exists with valid value"
},
"likelihood": 1,
"status": "pending"
}
]
}
Step 1.4: Add NDJSON Instrumentation
For each hypothesis, add logging at the specified location:
Python template:
# region debug [H{n}]
try:
import json, time
_dbg = {
"sid": "{sessionId}",
"hid": "H{n}",
"loc": "{file}:{line}",
"msg": "{testable_condition}",
"data": {
# Capture relevant values here
},
"ts": int(time.time() * 1000)
}
with open(r"{debugLogPath}", "a", encoding="utf-8") as _f:
_f.write(json.dumps(_dbg, ensure_ascii=False) + "\n")
except: pass
# endregion
JavaScript/TypeScript template:
// region debug [H{n}]
try {
require('fs').appendFileSync("{debugLogPath}", JSON.stringify({
sid: "{sessionId}",
hid: "H{n}",
loc: "{file}:{line}",
msg: "{testable_condition}",
data: { /* Capture relevant values */ },
ts: Date.now()
}) + "\n");
} catch(_) {}
// endregion
Step 1.5: Output to User
## Hypotheses Generated
Based on error "$BUG", generated {n} hypotheses:
{hypotheses.map(h => `
### ${h.id}: ${h.description}
- Logging at: ${h.logging_point}
- Testing: ${h.testable_condition}
- Evidence to confirm: ${h.evidence_criteria.confirm}
- Evidence to reject: ${h.evidence_criteria.reject}
`).join('')}
**Debug log**: ${debugLogPath}
**Next**: Run reproduction steps, then come back for analysis.
Analyze Mode
Step 2.1: Parse Debug Log
// Parse NDJSON log
const entries = Read(debugLogPath).split('\n')
.filter(l => l.trim())
.map(l => JSON.parse(l))
// Group by hypothesis
const byHypothesis = groupBy(entries, 'hid')
// Validate each hypothesis
for (const [hid, logs] of Object.entries(byHypothesis)) {
const hypothesis = hypotheses.find(h => h.id === hid)
const latestLog = logs[logs.length - 1]
// Check if evidence confirms or rejects hypothesis
const verdict = evaluateEvidence(hypothesis, latestLog.data)
// Returns: 'confirmed' | 'rejected' | 'inconclusive'
}
Step 2.2: Analyze Evidence and Correct Understanding
Review the debug log and evaluate each hypothesis:
- Parse all log entries
- Group by hypothesis ID
- Compare evidence against expected criteria
- Determine verdict: confirmed | rejected | inconclusive
- Identify incorrect assumptions from previous understanding
- Generate corrections
Step 2.3: Update Understanding with Corrections
Append new iteration to understanding.md:
### Iteration ${n} - Evidence Analysis (${timestamp})
#### Log Analysis Results
${results.map(r => `
**${r.id}**: ${r.verdict.toUpperCase()}
- Evidence: ${JSON.stringify(r.evidence)}
- Reasoning: ${r.reason}
`).join('\n')}
#### Corrected Understanding
Previous misunderstandings identified and corrected:
${corrections.map(c => `
- ~~${c.wrong}~~ → ${c.corrected}
- Why wrong: ${c.reason}
- Evidence: ${c.evidence}
`).join('\n')}
#### New Insights
${newInsights.join('\n- ')}
${confirmedHypothesis ? `
#### Root Cause Identified
**${confirmedHypothesis.id}**: ${confirmedHypothesis.description}
Evidence supporting this conclusion:
${confirmedHypothesis.supportingEvidence}
` : `
#### Next Steps
${nextSteps}
`}
---
## Current Consolidated Understanding (Updated)
${consolidatedUnderstanding}
Step 2.4: Update hypotheses.json
{
"iteration": 2,
"timestamp": "2025-01-21T10:15:00+08:00",
"hypotheses": [
{
"id": "H1",
"status": "rejected",
"verdict_reason": "Evidence shows key exists with valid value",
"evidence": {...}
},
{
"id": "H2",
"status": "confirmed",
"verdict_reason": "Log data confirms timing issue",
"evidence": {...}
}
],
"corrections": [
{
"wrong_assumption": "...",
"corrected_to": "...",
"reason": "..."
}
]
}
Fix & Verification
Step 3.1: Apply Fix
Based on confirmed hypothesis, implement the fix in the affected files.
Step 3.2: Document Resolution
Append to understanding.md:
### Iteration ${n} - Resolution (${timestamp})
#### Fix Applied
- Modified files: ${mo
---
*Content truncated.*
When not to use it
- →Simple, one-off bug fixes
- →Bugs requiring immediate hotfixes
Prerequisites
Limitations
- →Requires manual reproduction steps
- →Overhead for simple issues
How it compares
This method forces a rigorous, documented process for complex bugs, whereas standard debugging often lacks a persistent record of failed attempts.
Compared to similar skills
debug-with-file side by side with the closest alternatives in the catalog.
| Skill | Installs | Updated | Safety | Difficulty |
|---|---|---|---|---|
| debug-with-file (this skill) | 1 | 3mo | Review | Advanced |
| python-testing-patterns | 77 | 2mo | Review | Intermediate |
| error-handling-patterns | 35 | 2mo | No flags | Intermediate |
| codex-claude-loop | 13 | 9mo | Review | Advanced |
Try saying
Example prompts that trigger this skill in your AI assistant.
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