Describe hints tier 3: callers, members, EXTENDS (gated)

[HumanBean17]

Summary

Follow-up to propose/DESCRIBE-HINTS-STRUCTURAL-PROPOSE.md (tiers 1–2). Tier 3 covers lower-ROI or noise-prone describe road-sign templates. Implement only if tier 1–2 land and agent traces still show stalls on these patterns.

Tier 3 scope (deferred)

ID	Trigger (sketch)	Template	Gate / risk
F	method, CALLS.in > 0, CALLS.out = 0	callers: neighbors(['{id}'],'in',['CALLS'])	High noise on DTO getters (~200 methods on bank fixture). Require role in {SERVICE, CONTROLLER, COMPONENT, REPOSITORY} and/or CALLS.in >= 2.
K	type, DECLARES.out > 0, no other tier-1/2 signals	members: neighbors(['{id}'],'out',['DECLARES'])	Weak signal; agents often guess.
L	type, EXTENDS.out > 0, no rollups	supertype: neighbors(['{id}'],'out',['EXTENDS'])	Repo interfaces extending JpaRepository; secondary to implementor/injector hints.

Out of scope

• New graph edges or ontology_version bump
• Pre-fetching neighbors results inside describe
• Per-row hints on NodeRecord.data

Acceptance (if picked up)

• Each row has a named test_hints_describe_* in tests/test_mcp_hints.py on tests/bank-chat-system or a focused fixture
• Rendered hints ≤ 120 chars; cap/dedupe unchanged
• Negative tests: DTO getter must not emit F when gates are applied

References

• Landed catalog: propose/completed/HINTS-ROAD-SIGNS-PROPOSE.md (deferred IMPLEMENTS / EXTENDS §5)
• v4 neighbors/find parity: propose/completed/HINTS-V4-SUCCESS-PATH-PROPOSE.md

[HumanBean17]

Tier 1–2 spec: propose/DESCRIBE-HINTS-STRUCTURAL-PROPOSE.md (in-flight). Implement tier 3 after that PR lands, or if traces still show stalls on callers/members/EXTENDS.