- name
- prp-codebase-question
- description
- Research codebase questions using parallel agents - documents what exists, not what should change. Use when the user asks how the codebase works, where something lives, or invokes /prp-codebase-question.
- argument-hint
- <question or topic> [--web] [--follow-up]
# Codebase Research
**Input**: $ARGUMENTS
---
## Your Mission
Answer codebase questions thoroughly by spawning parallel specialized agents, synthesizing their findings, and producing a research document.
**Core Philosophy**: Document what IS, not what SHOULD BE. You are a technical cartographer.
**Golden Rule**: Every claim must have a `file:line` reference. No speculation, no suggestions, no critique.
---
## CRITICAL: Documentarian Only
- **DO NOT** suggest improvements or changes
- **DO NOT** perform root cause analysis unless explicitly asked
- **DO NOT** propose future enhancements
- **DO NOT** critique implementations or identify problems
- **DO NOT** recommend refactoring or optimization
- **ONLY** describe what exists, where it exists, how it works, and how components interact
---
## Phase 1: PARSE - Understand the Query
### 1.1 Read Mentioned Files
If the user mentions specific files, read them FULLY first (no limit/offset) before any decomposition.
### 1.2 Classify the Query
| Type | Indicators | Agent Focus |
|------|-----------|-------------|
| **Where** | "where is", "find", "locate" | `prp-core:codebase-explorer` primary |
| **How** | "how does", "trace", "flow" | `prp-core:codebase-analyst` primary |
| **What** | "what is", "explain", "describe" | Both agents in parallel |
| **Pattern** | "how do we", "convention", "examples" | `prp-core:codebase-explorer` primary |
| **External** | "docs", "best practice", "API" | Add `prp-core:web-researcher` |
### 1.3 Determine Scope
- Identify specific components, patterns, or concepts to investigate
- Note any `--web` flag for external research
- Note any `--follow-up` flag for appending to existing research
**PHASE_1_CHECKPOINT:**
- [ ] Mentioned files read in full
- [ ] Query type classified
- [ ] Research scope identified
- [ ] Flags parsed (--web, --follow-up)
---
## Phase 2: DECOMPOSE - Break into Research Areas
### 2.1 Create Research Plan
Break the query into 2-5 composable research areas:
```
RESEARCH QUESTION: {user's question}
AREAS:
1. {Area} → Agent: {which agent}
2. {Area} → Agent: {which agent}
3. {Area} → Agent: {which agent}
```
### 2.2 Agent Selection
| Agent | Use When |
|-------|----------|
| `prp-core:codebase-explorer` | Finding WHERE code lives, locating files, extracting patterns, discovering conventions |
| `prp-core:codebase-analyst` | Understanding HOW code works, tracing data flow, mapping integration points |
| `prp-core:web-researcher` | Only when `--web` flag is set or user explicitly asks for external docs |
**Strategy:**
1. Start with `prp-core:codebase-explorer` to find what exists
2. Then use `prp-core:codebase-analyst` on the most relevant findings to trace how they work
3. Run agents in parallel when they're searching for different areas
**PHASE_2_CHECKPOINT:**
- [ ] Query decomposed into 2-5 research areas
- [ ] Agent assigned to each area
- [ ] Parallel vs sequential execution planned
---
## Phase 3: EXPLORE - Spawn Parallel Agents
### 3.1 Launch Codebase Agents
**Launch agents in parallel using multiple Task tool calls in a single message.**
For each research area, use the appropriate agent:
**`prp-core:codebase-explorer`:**
```
Find all code relevant to: {research area}
LOCATE:
1. {Specific files/components to find}
2. {Patterns or conventions to extract}
3. {Related test files and configuration}
Categorize findings by purpose. Return ACTUAL code snippets with file:line references.
Remember: Document what exists, no suggestions or improvements.
```
**`prp-core:codebase-analyst`:**
```
Analyze the implementation of: {research area}
TRACE:
1. {Data flow to trace}
2. {Integration points to document}
3. {Contracts between components}
Document what exists with precise file:line references. No suggestions.
```
### 3.2 Launch Web Research (if --web or explicitly requested)
**`prp-core:web-researcher`:**
```
Research external documentation for: {topic}
FIND:
1. {Specific documentation needed}
2. {API references or patterns}
Return findings with direct links and citations.
```
### 3.3 Wait for All Agents
**IMPORTANT**: Wait for ALL agents to complete before proceeding.
**PHASE_3_CHECKPOINT:**
- [ ] All agents launched (parallel where possible)
- [ ] All agents completed
- [ ] Results collected from each agent
---
## Phase 4: SYNTHESIZE - Merge Findings
### 4.1 Compile Results
- Prioritize live codebase findings as primary source of truth
- Connect findings across different components
- Include specific `file:line` references throughout
- Document patterns, connections, and architectural decisions as they exist
### 4.2 Answer the Question
Map findings back to the user's original question:
| Question Aspect | Finding | Evidence |
|----------------|---------|----------|
| {aspect 1} | {what was found} | `file.ts:123` |
| {aspect 2} | {what was found} | `file.ts:456` |
### 4.3 Identify Gaps
Note any areas that couldn't be fully documented:
- {Area that needs further investigation}
- {Question that remains open}
**PHASE_4_CHECKPOINT:**
- [ ] All agent results synthesized
- [ ] Findings connected across components
- [ ] Original question answered with evidence
- [ ] Gaps identified
---
## Phase 5: DOCUMENT - Generate Research File
### 5.1 Gather Metadata
```bash
date -u +"%Y-%m-%dT%H:%M:%SZ"
git rev-parse --short HEAD
git branch --show-current
basename $(git rev-parse --show-toplevel)
```
### 5.2 Create Research Directory
```bash
mkdir -p .claude/PRPs/research
```
### 5.3 Determine Filename
**If --follow-up**: Append to existing research file instead of creating new one.
**If new research**:
**Path**: `.claude/PRPs/research/{YYYY-MM-DD}-{kebab-case-topic}.md`
Examples:
- `2025-01-08-authentication-flow.md`
- `2025-01-15-database-migration-patterns.md`
### 5.4 Write Research Document
```markdown
---
date: {ISO timestamp with timezone}
git_commit: {short hash}
branch: {branch name}
repository: {repo name}
topic: "{User's Question/Topic}"
tags: [research, codebase, {relevant-component-names}]
status: complete
last_updated: {YYYY-MM-DD}
---
# Research: {User's Question/Topic}
**Date**: {ISO timestamp}
**Git Commit**: {short hash}
**Branch**: {branch name}
**Repository**: {repo name}
## Research Question
{Original user query}
## Summary
{High-level documentation of what was found, answering the question by describing what exists}
## Detailed Findings
### {Component/Area 1}
- Description of what exists (`file.ts:123`)
- How it connects to other components
- Current implementation details
### {Component/Area 2}
...
## Code References
| File | Lines | Description |
|------|-------|-------------|
| `path/to/file.ts` | 123-145 | {What's there} |
| `another/file.ts` | 45-67 | {What's there} |
## Architecture Documentation
{Current patterns, conventions, and design implementations found}
## Open Questions
- {Areas that need further investigation}
```
### 5.5 Add GitHub Permalinks (if applicable)
```bash
# Check if on main or pushed
git branch --show-current
gh repo view --json owner,name -q '"\(.owner.login)/\(.name)"'
```
If on main/pushed, replace local file references with:
`https://github.com/{owner}/{repo}/blob/{commit}/{file}#L{line}`
### 5.6 Handle Follow-ups
If `--follow-up` flag and existing research file:
1. Read the existing research file
2. Update frontmatter: `last_updated` and add `last_updated_note`
3. Append new section: `## Follow-up Research {timestamp}`
4. Spawn new agents as needed
5. Save updated document
**PHASE_5_CHECKPOINT:**
- [ ] Metadata gathered
- [ ] Research file created (or existing file updated for follow-up)
- [ ] All sections filled with evidence-based content
- [ ] GitHub permalinks added (if applicable)
- [ ] No placeholder values remain
---
## Phase 6: OUTPUT - Present to User
```markdown
## Research Complete
**Question**: {original question}
**Document**: `.claude/PRPs/research/{filename}.md`
### Summary
{2-3 sentence answer to the question}
### Key Findings
- **{Finding 1}**: {brief} (`file.ts:123`)
- **{Finding 2}**: {brief} (`file.ts:456`)
- **{Finding 3}**: {brief} (`file.ts:789`)
### Architecture
{1-2 sentence description of relevant architecture}
### Open Questions
- {Any unanswered aspects}
### Follow-up
To dig deeper: `/prp-codebase-question --follow-up {topic}`
To include external docs: `/prp-codebase-question --web {topic}`
```
---
## Usage Examples
```bash
# Basic codebase question
/prp-codebase-question how does authentication work
# Include external documentation
/prp-codebase-question --web how does the PRP runner execute commands
# Follow up on previous research
/prp-codebase-question --follow-up what error handling patterns exist in the runner
# Locate and document a specific area
/prp-codebase-question where are all the command templates and how are they structured
```
---
## Critical Reminders
1. **Document, don't evaluate.** Describe what IS, never what SHOULD BE.
2. **Evidence required.** Every claim needs a `file:line` reference.
3. **Agents are parallel.** Launch multiple agents simultaneously when researching different areas.
4. **Wait for completion.** Never synthesize until ALL agents have returned.
5. **Read first.** If the user mentions files, read them fully before spawning agents.
6. **No placeholders.** Every field in the research document must have real values.
7. **Codebase is truth.** Live code always overrides documentation or assumptions.
---
## Success Criteria
- **QUESTION_ANSWERED**: User's question addressed with concrete evidence
- **AGENTS_USED**: Specialized agents spawned for each research area
- **EVIDENCE_COMPLETE**: Every finding has `file:line` references
- **DOCUMENT_CREATED**: Research file saved at `.claude/PRPs/research/`
- **NO_OPINIONS**: Document describes what exists, not what should change
- **PERMALINKS_ADDED**: GitHub links included when possible
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