Base

You are working in aspens — a CLI that keeps coding-agent context accurate as your codebase changes. Scans repos, generates project-specific instructions and skills for Claude Code and Codex CLI, and keeps them fresh.

Tech Stack

Node.js 20+ (ESM) | Commander | Vitest | es-module-lexer | @clack/prompts | picocolors

Commands

• npm test — Run vitest suite
• npm start / node bin/cli.js — Run CLI
• aspens scan [path] — Deterministic repo analysis (no LLM)
• aspens doc init [path] — Generate skills + hooks + CLAUDE.md (--target claude|codex|all, --recommended for full recommended setup)
• aspens doc impact [path] — Show freshness, coverage, and drift of generated context (--apply for auto-repair, --backend/--model/--timeout/--verbose for LLM interpretation)
• aspens doc sync [path] — Incremental skill updates from git diffs
• aspens doc graph [path] — Rebuild import graph cache (.claude/graph.json)
• aspens add [name] — Install templates (agents, commands, hooks)
• aspens customize agents — Inject project context into installed agents
• aspens save-tokens [path] — Install token-saving session settings (--recommended for no-prompt install, --remove to uninstall)
• Debug: ASPENS_DEBUG=1 dumps raw stream events to $TMPDIR/aspens-debug-{stream,codex-stream}.json
• Env knob: ASPENS_TIMEOUT (seconds) overrides default LLM timeout when --timeout not passed

Architecture

CLI entry (bin/cli.js) → command handlers (src/commands/) → lib modules (src/lib/)

• src/lib/scanner.js — Deterministic repo scanner (languages, frameworks, domains, structure)
• src/lib/graph-builder.js — Static import analysis via es-module-lexer (hub files, clusters, priority)
• src/lib/graph-persistence.js — Graph serialization, subgraph extraction, code-map + index generation
• src/lib/runner.js — Claude/Codex CLI wrapper (runClaude for stream-json, runCodex for Codex JSONL); also hosts loadPrompt (partial substitution) and parseFileOutput/validateSkillFiles
• src/lib/context-builder.js — Assembles repo files into prompt-friendly context
• src/lib/skill-writer.js — Writes skill files and directory-scoped files, generates skill-rules.json, merges settings
• src/lib/skill-reader.js — Parses skill files, frontmatter, triggers: blocks, legacy activation patterns, keywords
• src/lib/diff-classifier.js — Maps changed files to affected skills for doc-sync
• src/lib/diff-helpers.js — Targeted file diffs and prioritized diff truncation for doc-sync
• src/lib/git-helpers.js — Git repo detection, git root resolution, diff retrieval, log formatting
• src/lib/git-hook.js — Post-commit git hook installation/removal for auto doc-sync (monorepo-aware)
• src/lib/impact.js — Context health analysis: domain coverage, hub surfacing, drift detection, hook health, save-tokens health, usefulness summary, value comparison, opportunities
• src/lib/save-tokens.js — Save-tokens config defaults, settings builders, gitignore/readme generators
• src/lib/timeout.js — Timeout resolution (--timeout flag > ASPENS_TIMEOUT env > default)
• src/lib/errors.js — CliError class (structured errors caught by CLI top-level handler)
• src/lib/target.js — Target definitions (claude/codex), config persistence (.aspens.json) with saveTokens feature config; getAllowedPaths for multi-target sanitization
• src/lib/target-transform.js — Transforms Claude-format output to other target formats
• src/lib/backend.js — Backend detection and resolution (which CLI generates content)
• src/lib/path-resolver.js / src/lib/source-exts.js — Source-file extension and path resolution helpers shared by scanner/graph
• src/lib/parsers/ — Language-specific import parsers (TypeScript, Python)
• src/lib/frameworks/ — Framework-specific detectors (e.g. Next.js)
• src/prompts/ — Prompt templates with {{partial}} and {{variable}} substitution
• src/templates/ — Bundled agents, commands, hooks, and settings for aspens add / doc init / save-tokens

Critical Conventions

• Pure ESM — "type": "module" throughout; use import/export, never require()
• es-module-lexer WASM — must await init before calling parse() in graph-builder
• Claude CLI execution — runClaude() spawns claude -p with stream-json; always use --verbose flag with stream-json
• Codex CLI execution — runCodex() spawns codex exec --json --sandbox read-only --ask-for-approval never --ephemeral; returns { text, usage } matching runClaude interface
• Stdin with backpressure — runClaude/runCodex pipe prompts via stdin and respect drain when write() returns false; never rewrite to use args (shell length limits)
• Path sanitization — parseFileOutput() restricts writes to .claude/ and CLAUDE.md by default; accepts allowedPaths override for multi-target via getAllowedPaths(targets)
• Read-only LLM tools — customize-style commands pass allowedTools: ['Read', 'Glob', 'Grep']; never broaden without review
• Prompt partials — {{name}} in prompt files resolves to src/prompts/partials/name.md first, then falls back to template variables
• Target/Backend distinction — Target = output format/location; Backend = which LLM CLI generates content. Config persisted in .aspens.json. Customize is Claude-only (CliError if targets: ['codex'])
• Scanner is deterministic — no LLM calls; pure filesystem analysis
• CliError pattern — command handlers throw CliError instead of calling process.exit(); caught at top level in bin/cli.js
• Monorepo support — getGitRoot() resolves the actual git root; hooks, sync, and impact scope to the subdirectory project path
• Verify before claiming — Never state something is configured/running/done without confirming in-session

Structure

• bin/ — CLI entry point (commander setup, CliError handler)
• src/commands/ — Command handlers (scan, doc-init, doc-impact, doc-sync, doc-graph, add, customize, save-tokens)
• src/lib/ — Core library modules
• src/prompts/ — Prompt templates + partials
• src/templates/ — Installable agents, commands, hooks, settings
• tests/ — Vitest test files

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Last Updated: 2026-05-11

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: aspenkit
• Source: aspenkit/aspens
• License: MIT
• Homepage: https://www.npmjs.com/package/aspens

Install and usage instructions live in the source repository linked above.