Model issued MCP trace calls by bare symbol name without uids; five of six failed

**What happened**
The model called the GitNexus trace tool with common names (execute, run, start, execution) plus file hints. Results: one path found, three no_path, one ambiguous, one truncated. Earlier context results had returned exact uids the model did not reuse.

**Expected**
from_uid and to_uid from prior results, and a lower depth.

**Repro**
Call trace with names shared by many symbols in a large repository.

**Environment:** Claude Code CLI 2.1.270 (Claude Code), macOS, auto mode, model claude-fable-5-1, session of 2026-09-14.