/craft:explain

Usage:

• /craft:explain <domain> <subject> explains the subject: a file, a query, a schema source.
• /craft:explain sql <query file> walks a query in execution order.
• /craft:explain sql <ddl, migrations dir or dump> describes the database it defines.

Scope: one subject to one document with no questions. Not in scope: proposing a change
(/craft:discuss), running the thing explained, or serving the page (/craft:parley).

Inputs: the domain, the subject, and the domain note domains/<domain>.md beside this skill.
Output: docs/parley/<id>.json, checked and served, with no questions.

What an explanation is

• Blocks from the domain note, in reading order; a prose block first when the subject needs
  framing.
• Every node anchored to the exact text it explains (a TextQuoteSelector) and, when the
  subject lives in the repo, carrying source so the page links to the lines.
• summary in one line and detail in two to four short paragraphs per node.
• A warning for every silent-failure case the reader could miss.
• No questions. Where the subject embeds a choice, say so in the node's detail; a decision is
  /craft:discuss.

Steps

1. Read the domain note and the subject; name the dialect or language. If the domain has no
   note, say so, suggest one, and proceed on the block types alone (/craft:parley).
2. List the nodes in the order the domain note asks for and give each a stable id, a word
   never a number.
3. For each node write the anchor, title, summary, detail and warnings, and the domain's extra
   fields.
4. Write docs/parley/<id>.json, id being the kebab-case title, and run /craft:parley check.
5. Run /craft:parley serve, which starts the listener, and give the link. Answer each comment
   as it arrives, without waiting to be told.

Grading

• Every anchor resolves and the nodes read in the domain note's order.
• Every node's detail says more than its summary.
• The document has no questions.
• A rewrite keeps every node id.

Test environment

examples/sql/orders-query-explained.json and examples/sql/orders-schema.json beside
/craft:parley are reference outputs. Explain their subjects from scratch and compare.