subagent-gen

name	subagent-gen
version	1.1.1
description	Generate a persistent PROJECT-KNOWLEDGE.md profile for any codebase that gives subagents instant deep domain expertise. Analyzes project structure, architecture, code conventions, tech stack, data flow, and domain concepts. The profile is designed to be loaded into Agent tool prompts so subagents can answer deep codebase questions like an expert teammate. Use when the user asks to profile a project, generate project knowledge, create a codebase profile, build a context pack, analyze a codebase for subagents, or says "profile this project". Trigger phrases include "profile project", "generate project knowledge", "codebase profile", "subagent context", "knowledge profile", "project profile", "profile this codebase", "build project knowledge", "create context pack", "generate codebase knowledge", "index this project", "make subagent", "generate subagent", "deep knowledge", "project expert".

Subagent Knowledge Profile Generator

Generate a persistent PROJECT-KNOWLEDGE.md that captures deep domain knowledge about a codebase, designed to fit in a subagent prompt context window.

Locating your own reference files

Every references/*.md mention below is relative to this skill's own install location, not to the project being profiled (--project) — your working directory is the target project, so a bare relative path will not resolve. Resolve it once, in one Bash call, at the top of the workflow:

SKILL_HOME=$(ls -d ~/.claude/plugins/cache/hideki-plugins/subagent-gen/*/skills/subagent-gen 2>/dev/null | sort -V | tail -1)
echo "$SKILL_HOME"

Re-derive $SKILL_HOME in the same Bash call as any later read — shell state doesn't persist between separate Bash tool calls. This is also the "skill resource dir" to pass to the synthesis subagent in Phase 3 (its own input contract expects it as an absolute path, not a relative one).

Arguments

Parse these from the user's invocation. All are optional with defaults:

Argument	Default	Description
--project	cwd	Path to the project to profile
--name	(auto)	Profile name — used as filename in ~/.claude/knowledge/. Auto-derived from manifest or directory name
--output	~/.claude/knowledge/{name}.md	Override the canonical output path
--update	false	Refresh an existing profile incrementally
--depth	standard	quick (~2K words), standard (~4K words), deep (~6K words)
--focus	all	Comma-separated subset: structure, architecture, conventions, domain
--list	false	List all available profiles in ~/.claude/knowledge/ and stop

Workflow

Phase 0: List Profiles (if --list)

If --list is passed, list all *.md files in ~/.claude/knowledge/:

ls -la ~/.claude/knowledge/*.md 2>/dev/null

For each file, parse the header line to extract project name, generation date, depth, and source path. Display as a table:

Profile	Generated	Depth	Source Path
{name}	{date}	{depth}	{path}

Then stop — do not proceed to profiling.

Feedback Check

If feedback/log.md exists and has 5 or more entries, read the last 10 entries. If a pattern is apparent (same issue in 3+ entries, or average rating below 3):

• Tell the user: "Recurring feedback detected: [brief pattern]. Consider running /skill-improve --skill subagent-gen."
• Continue with normal execution.

Phase 1: Identify Target Project

1. Use --project path or current working directory
2. Verify it contains source files (not empty or config-only)
3. Derive --name if not provided:
   • Read package.json → use name field
   • Read pyproject.toml → use [project] name
   • Read Cargo.toml → use [package] name
   • Fallback: use the directory basename, lowercased, hyphens for spaces
4. If --update, check for existing profile at ~/.claude/knowledge/{name}.md first, then fall back to .agent/local/PROJECT-KNOWLEDGE.md
5. Read .gitignore to understand exclusion patterns

If the directory is empty or has no source files, report "No source files found" and stop.

Phase 2: Reconnaissance (Inline)

Quick inline scan — no subagents needed. Gather metadata for Phase 3.

1. Read root manifests: Look for package.json, pyproject.toml, Cargo.toml, go.mod, pom.xml, build.gradle, *.sln, *.csproj, Gemfile, composer.json, mix.exs, CMakeLists.txt, Makefile, Dockerfile, docker-compose.yml
2. Directory tree: Use Glob/Bash to map top 3 levels of the directory tree
3. File census: Count source files vs test files vs config files by extension
4. Detect stack: From manifests, identify:
   • Primary language(s) and version(s)
   • Framework(s)
   • Build system / package manager
   • Test runner(s)
   • Whether it's a monorepo (multiple package.json / workspace config)

Produce a metadata block in this format to pass to Phase 3 agents:

PROJECT METADATA
================
Name: {project name from manifest}
Path: {absolute path}
Language(s): {e.g., TypeScript 85%, Python 15%}
Framework(s): {e.g., Next.js 14, FastAPI}
Build: {e.g., pnpm, turborepo}
Test runner: {e.g., vitest, pytest}
Monorepo: {yes/no — packages: ...}
Source dirs: {e.g., src/, api/, packages/}
Test dirs: {e.g., __tests__/, tests/, e2e/}
File count: {e.g., 342 source, 89 test, 45 config}

Phase 3: Parallel Deep Exploration

Read "$SKILL_HOME"/references/exploration-dimensions.md for the full pattern catalog for each dimension.

Spawn Explore-type subagents in parallel. Each agent receives:

• The project path
• The metadata block from Phase 2
• Its specific exploration instructions from the dimension catalog

Agent Configuration by Depth

--depth=quick — 2 agents:

Agent	Combined Dimensions
structure-architecture	Structure + Architecture: directory layout, entry points, module boundaries, how modules connect, data flow, layering
conventions-domain	Conventions + Domain: naming patterns, error handling, key abstractions, API surface, config

--depth=standard — 4 agents:

Agent	Dimension
structure-agent	Directory layout, entry points, module boundaries, build outputs
architecture-agent	Module connections, dependency graph, data flow, layering, state management
conventions-agent	Naming patterns, error handling, logging, validation, testing patterns
domain-agent	Business/domain concepts, key abstractions, API surface, configuration

--depth=deep — 4 agents with expanded scope: Same agents as standard, but each samples more files (20-30 instead of 10-15) and traces deeper dependency chains. Architecture agent also maps middleware chains and plugin systems.

Agent Prompt Template

For each agent, construct a prompt like:

You are analyzing a codebase to build a deep knowledge profile.

PROJECT METADATA
================
{paste metadata block from Phase 2}

YOUR DIMENSION: {dimension name}
=================================
{paste the relevant section from "$SKILL_HOME"/references/exploration-dimensions.md}

INSTRUCTIONS:
- Explore the project at {project path}
- Follow the exploration patterns and grep signals listed above
- Sample {10-15 | 20-30} files across different directories
- For every finding, include the concrete file path and specific detail
- Do NOT include vague descriptions — every bullet must have a file path or function name
- Output your findings in the exact markdown format specified in the dimension catalog

Report back your findings as a structured markdown block.

Focus Filtering

If --focus is set to specific dimensions (e.g., --focus=structure,domain), only spawn agents for those dimensions. Skip the others.

Monorepo Handling

If the project is a monorepo with multiple packages:

1. Ask the user which package(s) to profile, or whether to profile the root structure
2. If profiling specific packages, scope each agent's exploration to those package directories
3. If profiling root, focus on workspace config, shared utilities, and cross-package patterns

Large Project Handling (>5000 files)

1. Warn the user about project size
2. Suggest using --focus to narrow scope
3. Instruct agents to use sampling: read representative files from each directory rather than exhaustive scans
4. Cap the number of files each agent reads to 30

Phase 4: Synthesize Profile (delegated)

Hand the metadata block + all collected agent findings to @agent-subagent-gen:subagent-gen along with:

• target depth (quick / standard / deep)
• --focus filter
• --output path
• --update flag (if set)
• the skill resource dir so the subagent can read "$SKILL_HOME"/references/profile-template.md and "$SKILL_HOME"/references/prompt-integration-guide.md

The subagent does the synthesis, quality-checks every bullet (every line must carry a file path / identifier / pattern name / concrete value), enforces word-count targets, preserves <!-- USER: ... --> blocks in update mode, writes the profile to the canonical path, and creates the .agent/local/PROJECT-KNOWLEDGE.md symlink (falling back to copy on Windows without Developer Mode).

The subagent returns:

{
  "profile_path_global": "~/.claude/knowledge/{name}.md",
  "profile_path_local": ".agent/local/PROJECT-KNOWLEDGE.md",
  "word_count": 4123,
  "depth": "standard",
  "sections_preserved_from_user": ["..."],
  "key_findings": ["..."],
  "gitignore_suggestion": ".agent/local/"
}

Phase 5: Present Summary

Use the subagent's return value to show the user:

• Profile name and word count
• Global path: ~/.claude/knowledge/{name}.md (accessible from any project)
• Local path: .agent/local/PROJECT-KNOWLEDGE.md (symlinked for convenience)
• 3-5 key findings highlights (most interesting / non-obvious)
• If gitignore_suggestion came back, mention adding .agent/local/ to .gitignore
• How to use the profile (read "$SKILL_HOME"/references/prompt-integration-guide.md):
  • Same project: Read .agent/local/PROJECT-KNOWLEDGE.md for context, then: <task>
  • Cross-project: Read ~/.claude/knowledge/{name}.md for context, then: <task>
  • List all profiles: /subagent-gen --list

Error Handling

Situation	Behavior
Empty directory / no source files	Report and stop
Monorepo detected	Ask user which packages to focus on
Very large project (>5000 files)	Warn, suggest --focus, use sampling
--update but no existing profile	Fall back to fresh generation
Agent exploration fails or times out	Report partial results, note incomplete dimensions
Unrecognized language/framework	Profile what can be inferred from file structure and naming
Symlink creation fails (Windows)	Copy the file instead, warn about manual sync
--name conflicts with existing profile	Ask user to confirm overwrite or choose a different name
~/.claude/knowledge/ doesn't exist	Create it automatically

Retrospective

After completing the workflow, reflect on the entire execution session:

1. Consider: Were there mid-session corrections? Rejected outputs? Plan changes? Errors?
2. Ask the user: "Quick feedback on this run? (1-5 rating, note any issues, or press enter to skip)"
3. If the user provides feedback OR if corrections/issues occurred during this session: a. Create feedback/ directory if it does not exist (header: # Feedback Log + blank line + <!-- Append new entries at the top. Do not edit previous entries. -->) b. Prepend a new entry after the header:

   ## <ISO-8601 timestamp>
   - **Skill Version**: <version from this file's frontmatter>
   - **Task**: <brief description>
   - **Outcome**: success | partial-success | failure | error
   - **Rating**: <N>/5 (or "—" if not provided)
   - **Corrections**: <mid-session corrections, or "none">
   - **Issues**: <specific problems, or "none">
   - **User Note**: <user's verbatim feedback, or "—">
   ---
   

4. If the user skips AND no corrections or issues occurred, end without recording.

Behavior Scenarios

Scenario: Generate fresh profile for a standard project
  Given the user is in a project directory with source code and no existing profile
  When the user says "profile this project" or "generate project knowledge"
  Then the skill scans the project, launches parallel exploration agents,
  synthesizes findings into PROJECT-KNOWLEDGE.md, saves to .agent/local/,
  and shows how to use the profile in subagent prompts

Scenario: Update an existing profile after codebase changes
  Given a PROJECT-KNOWLEDGE.md already exists in .agent/local/
  When the user says "update project profile" or invokes with --update
  Then the skill reads the existing profile, focuses exploration on changed files,
  preserves user-customized sections (<!-- USER: ... -->), regenerates machine
  sections, and shows what changed

Scenario: Quick profile for a small task
  Given the user needs a lightweight profile fast
  When the user says "quick project profile" or invokes with --depth=quick
  Then the skill runs 2 combined agents, produces a ~2000-word profile,
  and completes faster than standard depth

Scenario: Profile a specific project path (not cwd)
  Given the user wants to profile a project in a different directory
  When the user says "profile project at D:\Projects\my-app"
  Then the skill uses the specified path as the project root for all exploration

Scenario: Very large monorepo project
  Given the project has over 5000 files or is a monorepo with multiple packages
  When the user invokes the skill
  Then the skill warns about size, asks which packages to focus on (if monorepo),
  uses sampling strategies to stay within token budget, and generates a profile
  scoped to the selected packages

Scenario: Use a profile from another project
  Given the user has profiled Project A and is now working in Project B
  When the user spawns a subagent with "Read ~/.claude/knowledge/project-a.md for context"
  Then the subagent has deep knowledge of Project A while working in Project B

Scenario: List all available profiles
  Given the user has generated profiles for multiple projects
  When the user says "list project profiles" or invokes with --list
  Then the skill lists all profiles in ~/.claude/knowledge/ with name, date, and source path

References

• "$SKILL_HOME"/references/exploration-dimensions.md — Pattern catalog for each exploration dimension (what to look for, grep signals, sampling strategy, output format)
• "$SKILL_HOME"/references/profile-template.md — Exact PROJECT-KNOWLEDGE.md template with section specs and placeholder examples
• "$SKILL_HOME"/references/prompt-integration-guide.md — How to load the generated profile into subagent prompts (inclusion patterns, selective loading, examples)