understand-explain

name understand-explain description Use when you need a deep-dive explanation of a specific file, function, or module in the codebase argument-hint [file-path] /understand-explain Provide a thorough, in-depth explanation of a specific code component. Graph Structure Reference The knowledge graph JSON has this structure: project — {name, description, languages, frameworks, analyzedAt, gitCommitHash} nodes[] — each has {id, type, name, filePath?, summary, tags[], complexity, languageNotes?} Code node types: file, function, class, module, concept Non-code node types: config, document, service, table, endpoint, pipeline, schema, resource Domain/knowledge node types: domain, flow, step, article, entity, topic, claim, source IDs use the node type as prefix, e.g. file:path , function:path:name , config:path , article:path edges[] — each has {source, target, type, direction, weight} Key types: imports, contains, calls, depends_on, configures, documents, deploys, triggers, contains_flow, flow_step, related, cites layers[] — each has {id, name, description, nodeIds[]} tour[] — each has {order, title, description, nodeIds[]} How to Read Efficiently Use Grep to search within the JSON for relevant entries BEFORE reading the full file Only read sections you need — don't dump the entire graph into context Node names and summaries are the most useful fields for understanding Edges tell you how components connect — follow imports and calls for dependency chains Instructions Resolve the data directory $UA_DIR . Run UA_DIR=$([ -d .understand-anything ] && echo .understand-anything || echo .ua) — this is the legacy .understand-anything/ when it already exists, otherwise the new .ua/ . Check that $UA_DIR/knowledge-graph.json exists. If not, tell the user to run /understand first. Check graph freshness before using graph-derived context : Read project.gitCommitHash from the graph metadata as GRAPH_COMMIT_RAW . Resolve it as a commit before using it in any Git diff, then compare it with git rev-parse HEAD and inspect project-scoped committed and working-tree changes from the project root: GRAPH_COMMIT=$(git rev-parse --verify --end-of-options " ${GRAPH_COMMIT_RAW} ^{commit}" 2>/dev/null) git rev-parse HEAD git diff --name-only " $GRAPH_COMMIT " HEAD -- . git diff --cached --name-only -- . git diff --name-only -- . git ls-files --others --exclude-standard -- . The -- . pathspec is required: commits that only touch a sibling monorepo project must not make this graph stale. A hash mismatch alone is not stale when the project diff is empty. Ignore the selected data directory ( .ua/ or legacy .understand-anything/ ) in every command's output because it contains generated graph artifacts, not project source drift. If the committed diff or any working-tree command reports project files, warn before explaining that graph-derived context may omit those changes. Suggest: Run /understand to refresh the graph. Run the commit diff only when GRAPH_COMMIT_RAW resolves successfully. If the graph commit or Git metadata is missing, invalid, or unavailable, give a brief best-effort warning and continue instead of blocking. Find the target node — use Grep to search the knowledge graph for the component: "$ARGUMENTS" For file paths (e.g., src/auth/login.ts ): search for "filePath" matches For function notation (e.g., src/auth/login.ts:verifyToken ): search for the function name in "name" fields filtered by the file path Note the exact node id , type , summary , tags , and complexity Find all connected edges — Grep for the target node's ID in the edges section: "source" matches → things this node calls/imports/depends on (outgoing) "target" matches → things that call/import/depend on this node (incoming) Note the connected node IDs and edge types Read connected nodes — for each connected node ID from step 4, Grep for those IDs in the nodes section to get their name , summary , and type . This builds the component's neighborhood. Identify the layer — Grep for the target node's ID in the "layers" section to find which architectural layer it belongs to and that layer's description. Read the actual source file — Read the source file at the node's filePath for the deep-dive analysis. Explain the component in context : Its role in the architecture (which layer, why it exists) Internal structure (functions, classes it contains — from contains edges) External connections (what it imports, what calls it, what it depends on — from edges) Data flow (inputs → processing → outputs — from source code) Explain clearly, assuming the reader may not know the programming language Highlight any patterns, idioms, or complexity worth understanding