Sprang explain

In-depth explanation of a specific code component: what it does, why it exists, who changed it, what depends on it.

Arguments: <file path or path:functionName> (e.g. src/auth/login.ts or src/auth/login.ts:validatePassword)

Instructions

1. Check .sprang/knowledge-graph.json exists. If not, run the sprang-analyze skill first.

2. Call sprang_query with the argument to find the target node. Note its id, type, summary, tags, complexity, risk_score, risk_factors, structural_warnings, and decision_context.

3. Call sprang_node with the resolved node_id to get: layer (name + id), layer_mate_count, in_degree, out_degree, has_annotation, and the full 1-hop neighborhood with edge directions and types.

   • Outgoing edges → what this node imports, calls, or depends on
   • Incoming edges → what imports, calls, or depends on this node (blast radius)

4. Call sprang_why with the same node_id for decision context: commit history, primary_authors, last_changed, rationale_snippets, change_frequency, pr_references, and any team annotation.

5. Read the actual source file at filePath for its current state.

6. Produce a structured explanation:

   What it does

   2-3 paragraphs on purpose and responsibilities.

   Where it fits

   • Layer: layer name and why it belongs there
   • Imports: what it depends on and why
   • Used by: what calls or imports it — the blast radius

   How it works

   Walk through the key functions, classes, and logic with real line numbers.

   History & ownership

   • Last changed: date
   • Authors: primary authors
   • Change frequency: commits in the last 90 days
   • Why it exists: rationale from commit messages, if available

   Risk & warnings

   • Risk score and the factors driving it
   • Structural warnings: any smells detected
   • What to watch out for: practical advice

   Next steps

   Suggest edits only after checking risk_score. Offer sprang-diff to see whether this file is currently changing, or sprang-chat for follow-ups.

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