Interactive hypothesis-driven debugging with documented exploration, understanding evolution, and analysis-assisted correction.
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npx tessl skill review --optimize ./.codex/skills/debug-with-file/SKILL.mdEnhanced 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:
$BUG
Run ccw spec load --category debug for known issues, workarounds, and root-cause notes.
Session Detection:
├─ Check if debug session exists for this bug
├─ EXISTS + understanding.md exists → Continue mode
└─ NOT_FOUND → Explore mode
Explore Mode:
├─ Locate error source in codebase
├─ Document initial understanding in understanding.md
├─ Generate testable hypotheses with analysis validation
├─ Add NDJSON logging instrumentation
└─ Output: Hypothesis list + await user reproduction
Analyze Mode:
├─ Parse debug.log, validate each hypothesis
├─ Use analysis to evaluate hypotheses and correct understanding
├─ Update understanding.md with:
│ ├─ New evidence
│ ├─ Corrected misunderstandings (strikethrough + correction)
│ └─ Consolidated current understanding
└─ Decision:
├─ Confirmed → Fix root cause
├─ Inconclusive → Add more logging, iterate
└─ All rejected → Assisted new hypotheses
Fix & Cleanup:
├─ Apply fix based on confirmed hypothesis
├─ User verifies
├─ Document final understanding + lessons learned
├─ Remove debug instrumentation
└─ If not fixed → Return to Analyze mode检测项目根目录,确保 .workflow/ 产物位置正确:
PROJECT_ROOT=$(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 = "$BUG".toLowerCase().replace(/[^a-z0-9]+/g, '-').substring(0, 30)
const dateStr = getUtc8ISOString().substring(0, 10)
const sessionId = `DBG-${bugSlug}-${dateStr}`
const sessionFolder = `${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 ${sessionFolder}`)
}// Extract keywords from bug description
const keywords = extractErrorKeywords("$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)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
${initialConsolidatedUnderstanding}Analyze the bug and generate 3-5 testable hypotheses:
// Hypothesis generation based on error pattern
const HYPOTHESIS_PATTERNS = {
"not found|missing|undefined|未找到": "data_mismatch",
"0|empty|zero|registered": "logic_error",
"timeout|connection|sync": "integration_issue",
"type|format|parse": "type_mismatch"
}
function generateHypotheses(bugDescription, affectedLocations) {
// Generate targeted hypotheses based on error analysis
// Each hypothesis includes:
// - id: H1, H2, ...
// - description: What might be wrong
// - testable_condition: What to log
// - logging_point: Where to add instrumentation
// - evidence_criteria: What confirms/rejects it
return hypotheses
}Save to hypotheses.json:
{
"iteration": 1,
"timestamp": "2025-01-21T10:00:00+08:00",
"hypotheses": [
{
"id": "H1",
"description": "Data structure mismatch - expected key not present",
"testable_condition": "Check if target key exists in dict",
"logging_point": "file.py:func:42",
"evidence_criteria": {
"confirm": "data shows missing key",
"reject": "key exists with valid value"
},
"likelihood": 1,
"status": "pending"
}
]
}For each hypothesis, add logging at the specified location:
Python template:
# region debug [H{n}]
try:
import json, time
_dbg = {
"sid": "{sessionId}",
"hid": "H{n}",
"loc": "{file}:{line}",
"msg": "{testable_condition}",
"data": {
# Capture relevant values here
},
"ts": int(time.time() * 1000)
}
with open(r"{debugLogPath}", "a", encoding="utf-8") as _f:
_f.write(json.dumps(_dbg, ensure_ascii=False) + "\n")
except: pass
# endregionJavaScript/TypeScript template:
// region debug [H{n}]
try {
require('fs').appendFileSync("{debugLogPath}", JSON.stringify({
sid: "{sessionId}",
hid: "H{n}",
loc: "{file}:{line}",
msg: "{testable_condition}",
data: { /* Capture relevant values */ },
ts: Date.now()
}) + "\n");
} catch(_) {}
// endregion## Hypotheses Generated
Based on error "$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.// 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'
}Review the debug log and evaluate each hypothesis:
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}{
"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": "..."
}
]
}Based on confirmed hypothesis, implement the fix in the affected files.
Append to understanding.md:
### Iteration ${n} - Resolution (${timestamp})
#### Fix Applied
- Modified files: ${modifiedFiles.join(', ')}
- Fix description: ${fixDescription}
- Root cause addressed: ${rootCause}
#### Verification Results
${verificationResults}
#### Lessons Learned
What we learned from this debugging session:
1. ${lesson1}
2. ${lesson2}
3. ${lesson3}
#### Key Insights for Future
- ${insight1}
- ${insight2}Remove debug instrumentation by searching for region markers:
const instrumentedFiles = Grep({
pattern: "# region debug|// region debug",
output_mode: "files_with_matches"
})
for (const file of instrumentedFiles) {
// Remove content between region markers
removeDebugRegions(file)
}{projectRoot}/.workflow/.debug/DBG-{slug}-{date}/
├── debug.log # NDJSON log (execution evidence)
├── understanding.md # Exploration timeline + consolidated understanding
└── hypotheses.json # Hypothesis history with verdicts# Understanding Document
**Session ID**: DBG-xxx-2025-01-21
**Bug Description**: [original description]
**Started**: 2025-01-21T10:00:00+08:00
---
## Exploration Timeline
### Iteration 1 - Initial Exploration (2025-01-21 10:00)
#### Current Understanding
...
#### Evidence from Code Search
...
#### Hypotheses Generated
...
### Iteration 2 - Evidence Analysis (2025-01-21 10:15)
#### Log Analysis Results
...
#### Corrected Understanding
- ~~[wrong]~~ → [corrected]
#### Analysis Results
...
---
## Current Consolidated Understanding
### What We Know
- [valid understanding points]
### What Was Disproven
- ~~[disproven assumptions]~~
### Current Investigation Focus
[current focus]
### Remaining Questions
- [open questions]Each line is a JSON object:
{"sid":"DBG-xxx-2025-01-21","hid":"H1","loc":"file.py:func:42","msg":"Check dict keys","data":{"keys":["a","b"],"target":"c","found":false},"ts":1734567890123}| Field | Description |
|---|---|
sid | Session ID |
hid | Hypothesis ID (H1, H2, ...) |
loc | Code location |
msg | What's being tested |
data | Captured values |
ts | Timestamp (ms) |
First Call (BUG="error"):
├─ No session exists → Explore mode
├─ Extract error keywords, search codebase
├─ Document initial understanding in understanding.md
├─ Generate hypotheses
├─ Add logging instrumentation
└─ Await user reproduction
After Reproduction (BUG="error"):
├─ Session exists + debug.log has content → Analyze mode
├─ Parse log, evaluate hypotheses
├─ Update understanding.md with:
│ ├─ Evidence analysis results
│ ├─ Corrected misunderstandings (strikethrough)
│ ├─ New insights
│ └─ Updated consolidated understanding
├─ Update hypotheses.json with verdicts
└─ Decision:
├─ Confirmed → Fix → Document resolution
├─ Inconclusive → Add logging, document next steps
└─ All rejected → Assisted new hypotheses
Output:
├─ {projectRoot}/.workflow/.debug/DBG-{slug}-{date}/debug.log
├─ {projectRoot}/.workflow/.debug/DBG-{slug}-{date}/understanding.md (evolving document)
└─ {projectRoot}/.workflow/.debug/DBG-{slug}-{date}/hypotheses.json (history)| Situation | Action |
|---|---|
| Empty debug.log | Verify reproduction triggered the code path |
| All hypotheses rejected | Generate new hypotheses based on disproven assumptions |
| Fix doesn't work | Document failed fix attempt, iterate with refined understanding |
| >5 iterations | Review consolidated understanding, escalate with full context |
| Understanding too long | Consolidate aggressively, archive old iterations to separate file |
When updating "Current Consolidated Understanding":
Bad (cluttered):
## Current Consolidated Understanding
In iteration 1 we thought X, but in iteration 2 we found Y, then in iteration 3...
Also we checked A and found B, and then we checked C...Good (consolidated):
## Current Consolidated Understanding
### What We Know
- Error occurs during runtime update, not initialization
- Config value is None (not missing key)
### What Was Disproven
- ~~Initialization error~~ (Timing evidence)
- ~~Missing key hypothesis~~ (Key exists)
### Current Investigation Focus
Why is config value None during update?| Feature | Description |
|---|---|
| NDJSON logging | Structured debug log with hypothesis tracking |
| Hypothesis generation | Analysis-assisted hypothesis creation |
| Exploration documentation | understanding.md with timeline |
| Understanding evolution | Timeline + corrections tracking |
| Error correction | Strikethrough + reasoning for wrong assumptions |
| Consolidated learning | Current understanding section |
| Hypothesis history | hypotheses.json with verdicts |
| Analysis validation | At key decision points |
Best suited for:
Now execute the debug-with-file workflow for bug: $BUG
0f8e801
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