understand

name understand description Analyze a codebase to produce an interactive knowledge graph for understanding architecture, components, and relationships argument-hint ["[path] [--full|--auto-update|--no-auto-update|--review|--language <lang>|--exclude <patterns>]"] /understand Analyze the current codebase and produce a knowledge-graph.json file in the project's data directory ( .ua/ , or the legacy .understand-anything/ when it already exists). This file powers the interactive dashboard for exploring the project's architecture. Options $ARGUMENTS may contain: --full — Force a full rebuild, ignoring any existing graph --auto-update — Enable automatic graph updates on commit (writes autoUpdate: true to $UA_DIR/config.json ) --no-auto-update — Disable automatic graph updates (writes autoUpdate: false to $UA_DIR/config.json ) --review — Run full LLM graph-reviewer instead of inline deterministic validation --language <lang> — Generate all textual content (summaries, descriptions, tags, titles, languageNotes, languageLesson) in the specified language. Accepts ISO 639-1 codes ( zh , ja , ko , en , es , fr , de , etc.) or friendly names ( chinese , japanese , korean , english , spanish , etc.). Locale variants supported: zh-TW , zh-HK , etc. Defaults to en (English). Stores preference in $UA_DIR/config.json for consistency across incremental updates. --exclude <patterns> — Comma-separated glob patterns for additional files/directories to exclude from analysis (e.g., --exclude "tests/*,docs/*" ). These patterns take highest priority over built-in defaults and .understandignore rules. Supports gitignore syntax including ! negation. A directory path (e.g. /path/to/repo or ../other-project ) — Analyze the given directory instead of the current working directory Progress Reporting Throughout execution, report progress to the user at each phase transition and during batch processing. This keeps users informed on large codebases where analysis can take a long time. Phase transitions: At the start of each phase, print a status line: [Phase N/7] <phase name>... Example: [Phase 2/7] Analyzing files (12 batches)... Batch progress: During Phase 2, report each batch with its index and total: Analyzing batch X/N (files: foo.ts, bar.ts, ...) (list up to 3 filenames, then ... if more) Phase completion: When a phase finishes, briefly confirm: Phase N complete. <one-line summary of result> Example: Phase 1 complete. Found 247 files across 3 languages. Phase 0 — Pre-flight Determine whether to run a full analysis or incremental update. Resolve PROJECT_ROOT : Parse $ARGUMENTS for a non-flag token (any argument that does not start with -- ). If found, treat it as the target directory path. If the path is relative, resolve it against the current working directory. Verify the resolved path exists and is a directory (run test -d <path> ). If it does not exist or is not a directory, report an error to the user and STOP . Set PROJECT_ROOT to the resolved absolute path. If no directory path argument is found, set PROJECT_ROOT to the current working directory. Worktree redirect. If PROJECT_ROOT is inside a git worktree (not the main checkout), redirect output to the main repository root. Worktrees managed by Claude Code are ephemeral — the data directory ( .ua/ , or legacy .understand-anything/ ) written there is destroyed when the session ends, taking the knowledge graph with it (issue #133). Detect a worktree by comparing git rev-parse --git-dir against git rev-parse --git-common-dir ; in a normal checkout or submodule they resolve to the same path, in a worktree they differ and the parent of --git-common-dir is the main repo root. COMMON_DIR=$(git -C " $PROJECT_ROOT " rev-parse --git-common-dir 2>/dev/null) GIT_DIR=$(git -C " $PROJECT_ROOT " rev-parse --git-dir 2>/dev/null) if [ -n " $COMMON_DIR " ] && [ -n " $GIT_DIR " ]; then COMMON_ABS=$( cd " $PROJECT_ROOT " && cd " $COMMON_DIR " 2>/dev/null && pwd -P) GIT_ABS=$( cd " $PROJECT_ROOT " && cd " $GIT_DIR " 2>/dev/null && pwd -P) if [ -n " $COMMON_ABS " ] && [ " $COMMON_ABS " != " $GIT_ABS " ]; then MAIN_ROOT=$( dirname " $COMMON_ABS " ) if [ -d " $MAIN_ROOT " ] && [ " ${UNDERSTAND_NO_WORKTREE_REDIRECT:-0} " != "1" ]; then echo "[understand] Detected git worktree at $PROJECT_ROOT " echo "[understand] Redirecting output to main repo root: $MAIN_ROOT " echo "[understand] (Set UNDERSTAND_NO_WORKTREE_REDIRECT=1 to keep PROJECT_ROOT as the worktree.)" PROJECT_ROOT= " $MAIN_ROOT " fi fi fi Set UNDERSTAND_NO_WORKTREE_REDIRECT=1 if you intentionally want a per-worktree graph (rare — most users want the redirect). 1.5. Ensure the plugin is built. Later phases invoke Node scripts that import @understand-anything/core . On a fresh install packages/core/dist/ does not exist yet — build once. Important: do not assume the plugin root is simply two directories above the skill path string. In many installations ~/.agents/skills/understand is a symlink into the real plugin checkout. Prefer runtime-provided plugin roots first (for Claude), then fall back to universal symlinks, skill symlink resolution, and common clone-based install paths. Resolve the plugin root like this: SKILL_REAL=$( realpath ~/.agents/skills/understand 2>/dev/null || readlink -f ~/.agents/skills/understand 2>/dev/null || echo "" ) SELF_RELATIVE=$([ -n " $SKILL_REAL " ] && cd " $SKILL_REAL /../.." 2>/dev/null && pwd || echo "" ) COPILOT_SKILL_REAL=$( realpath ~/.copilot/skills/understand 2>/dev/null || readlink -f ~/.copilot/skills/understand 2>/dev/null || echo "" ) COPILOT_SELF_RELATIVE=$([ -n " $COPILOT_SKILL_REAL " ] && cd " $COPILOT_SKILL_REAL /../.." 2>/dev/null && pwd || echo "" ) PLUGIN_ROOT= "" for candidate in \ " ${CLAUDE_PLUGIN_ROOT} " \ " $HOME /.understand-anything-plugin" \ " $SELF_RELATIVE " \ " $COPILOT_SELF_RELATIVE " \ " $HOME /.codex/understand-anything/understand-anything-plugin" \ " $HOME /.opencode/understand-anything/understand-anything-plugin" \ " $HOME /.pi/understand-anything/understand-anything-plugin" \ " $HOME /understand-anything/understand-anything-plugin" ; do if [ -n " $candidate " ] && [ -f " $candidate /package.json" ] && [ -f " $candidate /pnpm-workspace.yaml" ]; then PLUGIN_ROOT= " $candidate " break fi done if [ -z " $PLUGIN_ROOT " ]; then echo "Error: Cannot find the understand-anything plugin root." echo "Checked:" echo " - ${CLAUDE_PLUGIN_ROOT:-<unset CLAUDE_PLUGIN_ROOT>} " echo " - $HOME /.understand-anything-plugin" echo " - ${SELF_RELATIVE:-<unresolved path derived from ~/.agents/skills/understand>} " echo " - ${COPILOT_SELF_RELATIVE:-<unresolved path derived from ~/.copilot/skills/understand>} " echo " - $HOME /.codex/understand-anything/understand-anything-plugin" echo " - $HOME /.opencode/understand-anything/understand-anything-plugin" echo " - $HOME /.pi/understand-anything/understand-anything-plugin" echo " - $HOME /understand-anything/understand-anything-plugin" echo "Make sure the plugin is installed correctly." exit 1 fi if [ ! -f " $PLUGIN_ROOT /packages/core/dist/index.js" ]; then cd " $PLUGIN_ROOT " && (pnpm install --frozen-lockfile 2>/dev/null || pnpm install) && pnpm --filter @understand-anything/core build fi If pnpm is missing, report to the user: "Install Node.js ≥ 22 and pnpm ≥ 10, then re-run /understand ." 1.7. Resolve the data directory $UA_DIR . All Understand-Anything artifacts live in the project's data directory. Resolve it once, now that $PROJECT_ROOT is known, and reuse $UA_DIR for every read and write in later phases: UA_DIR= " $PROJECT_ROOT / $([ -d " $PROJECT_ROOT /.understand-anything" ] && echo .understand-anything || echo .ua) " This keeps the legacy .understand-anything/ directory when it already exists (existing projects keep working with no migration) and uses the new .ua/ otherwise. Because each phase may run in a fresh shell, treat $UA_DIR — like $PROJECT_ROOT — as a value you carry forward and substitute; re-resolve it with the line above if a later command block needs it in a new shell. Get the current git commit hash: git rev-parse HEAD Create the intermediate and temp output directories: mkdir -p " $UA_DIR /intermediate" mkdir -p " $UA_DIR /tmp" 3.1. Purge stale trash dirs. Phase 7 cleanup mv s scratch dirs into .trash-<timestamp>/ rather than rm -rf ing them directly (see issue #301), so that destructive-action gates on hardened hosts don't trip on just-created paths. Reclaim the space here once the trash is older than 7 days — by this point any freshness-window check has long since stopped caring about those dirs: find " $UA_DIR /" -maxdepth 1 - type d -name '.trash-*' -mtime +7 - exec rm -rf {} + 2>/dev/null || true 3.5. Auto-update configuration: - If --auto-update is in $ARGUMENTS : write {"autoUpdate": true} to $UA_DIR/config.json - If --no-auto-update is in $ARGUMENTS : write {"autoUpdate": false} to $UA_DIR/config.json - These flags only set the config — analysis proceeds normally regardless. 3.6. Language configuration: - Parse $ARGUMENTS for --language <lang> flag. If found, extract the language code. - Language code normalization: Map friendly names to ISO codes: - chinese → zh , japanese → ja , korean → ko , english → en , spanish → es , french → fr , german → de , portuguese → pt , russian → ru , arabic → ar , etc. - Locale variants: zh-TW , zh-HK , zh-CN , pt-BR , etc. are preserved as-is. - If --language is NOT specified: - Stored preference wins. If $UA_DIR/config.json has an outputLanguage field, set $OUTPUT_LANGUAGE to it and skip the rest. - Otherwise detect (first run only). Infer the predominant language of the user's conversation as an ISO 639-1 code ( $DETECTED_LANG ). If it is en or cannot be confidently determined, set $OUTPUT_LANGUAGE=en and proceed silently — no prompt (English users see no change). - If $DETECTED_LANG ≠ en , confirm once before analyzing: tell the user you detected <language> and ask whether to generate all content in it; they press Enter/"yes" to accept, or type another language code/name to override (normalize via the friendly-name map above). If running non-interactively (no reply possible), skip the wait, use $DETECTED_LANG , and print a one-line notice instead of blocking. - Persist the resolved $OUTPUT_LANGUAGE (including en ) into config.json so it never re-prompts for this project. - If --language IS specified: - Update $UA_DIR/config.json with the new language: merge {"outputLanguage": "<lang>"} into existing config. - Store as $OUTPUT_LANGUAGE for use throughout all phases. - Language directive template: Store as $LANGUAGE_DIRECTIVE : markdown > **Language directive**: Generate all textual content (summaries, descriptions, tags, titles, languageNotes, languageLesson) in **{language}**. Maintain technical accuracy while using natural, native-level phrasing in the target language. Keep technical terms in English when no standard translation exists (e.g., "middleware", "hook", "barrel"). 3.7. Exclude patterns: - Parse $ARGUMENTS for --exclude <patterns> flag. If found, extract the comma-separated patterns string. - Split on commas, trim whitespace from each pattern, and filter out empty entries. - Store the patterns as $EXCLUDE_PATTERNS (comma-joined for passing to downstream scripts: "tests/*,docs/*" ). - These patterns take highest priority — they are applied on top of default patterns and .understandignore rules. Use ! prefix to force-include files that would otherwise be excluded. - Incremental preparation re-scans the current inventory, so newly supplied exclusions take effect immediately and remove any previously analyzed files they now cover. Check for subdomain knowledge graphs to merge: List all *knowledge-graph*.json files in $UA_DIR/ excluding knowledge-graph.json itself (e.g. frontend-knowledge-graph.json , backend-knowledge-graph.json ). If any subdomain graphs exist, run the merge script bundled with this skill (located next to this SKILL.md file — use the skill directory path, not the project root): python "<SKILL_DIR>/merge-subdomain-graphs.py" " $PROJECT_ROOT " The script discovers subdomain graphs, loads the existing knowledge-graph.json as a base (if present), and merges everything into knowledge-graph.json (deduplicating nodes and edges). Report the merge summary to the user, then continue with the merged graph. Check if $UA_DIR/knowledge-graph.json exists. If it does, read it. Check if $UA_DIR/meta.json exists. If it does, read its gitCommitHash and store it as $LAST_COMMIT_HASH . Decision logic: Condition Action --full flag in $ARGUMENTS Full analysis (all phases) No existing graph or meta Full analysis (all phases) Existing graph + explicit --exclude Run deterministic incremental preparation even when the commit hash is unchanged, so the new inventory rules take effect immediately --review flag + existing graph + unchanged commit hash Skip to Phase 6 (review-only — reuse existing assembled graph)