get_conversation_context — latent scope leakage #216

Problem

GetConversationContextTool is wired to workers via builder.rs:629 and orchestrator.rs:4601, but has 0 calls across all E2E runs (math + session, 195+ runs). The coordinator-driven loop (LOG-23514) makes it architecturally unnecessary — the coordinator's job is to fully resolve conversation context into self-contained task descriptions.

Keeping the tool creates a misleading escape hatch that masks coordinator failures instead of surfacing them. worker_preamble.md:25 references it, giving workers the impression they should use it.

Fix

• Delete tools/get_conversation_context.rs
• Remove orchestration_chat_history field from AgentConfig (config.rs)
• Remove registration logic in builder.rs:629-633
• Remove injection at orchestrator.rs:4601
• Remove reference in worker_preamble.md:25

Files

• tools/get_conversation_context.rs (delete)
• config.rs (orchestration_chat_history field + clone + debug)
• builder.rs (registration block)
• orchestrator.rs (injection)
• worker_preamble.md (line 25 reference)

Verification

• cargo build — no compilation errors from removed type
• cargo test — 580+ tests pass
• E2E: no behavioral change (tool was never called)

OTHER NOTES:

• registered on every worker, returns full user chat history
• remove simultaneously with ORCHESTRATION_GOAL