Keep schema nodes out of untyped semantic search (regression since schemas are embedded) #3565

Problem

Since schemas are embedded (4aad201f, "Let agents fetch NodeSpace's skills and schemas by task, embed schemas…"), a semantic search that names no type is flooded by schema nodes:

• nodespace search "Hall Nine" returns 17 hits, 13 of them schemas (e.g. "Horizontal Line").
• On another database, search "marketing budget" returns 16 hits: 14 schemas, with the one relevant note last and "Checkbox" first.
• With --type text the same query returns just the right note.
• v0.3.3 on the same content returned exactly the relevant hit.

Cause: the default Knowledge scope's allowlist includes schema (packages/core/src/ops/search_ops.rs, ~40-60), and SchemaNodeBehavior::get_embeddable_content now returns content (packages/core/src/behaviors/mod.rs, ~1385). The graph-degree boost likely lifts the well-connected schema nodes further.

Untyped search is step 1 of SKILL.md's workflow, so agents get schema noise instead of the user's notes.

Evidence: the 2026-10-05 validation of main a5068fb8. The transcript and DB copies are in the reporter's local scratch (val-1005/smoke/).

Documentation

• data-layer.md, semantic search: "Semantic search defaults to the Knowledge scope: documents and user-defined types, with system types such as skill left out … A search that names no type keeps the default scope."
• ADR-029 §5: SearchScope definitions.
• prompt-skill-system.md: fetching skills and schemas by task, which is why schemas are embedded.

Acceptance criteria

Revised 2026-10-05. Only the core (built-in) schemas leave the default scope. ADR-029 §5 keeps schema in Knowledge, so user-defined schemas stay findable by meaning there. The flood was the ~40 built-in schemas that are now embedded. The original criteria are kept below, struck through.

• An untyped search (default Knowledge scope) returns no core (built-in) schema nodes, and ranks the relevant user node first.
• An untyped search can still return a matching user-defined schema (e.g. "Venue" for a venue-like query).
• --type schema returns core schemas. The skill/schema fetch-by-task path (find_skills) and the desktop everything scope are unchanged.
• Tests pin each behaviour, each mutation-checked.

🤖 Generated with Claude Code