fix(mcp): select Location subfields for coordinate signals

[zer0stars]

Problem

The MCP shortcut tools telemetry_get_signals_time_series and telemetry_get_latest_signals render selection sets that only work for scalar signals. Any request naming currentLocationCoordinates / currentLocationApproximateCoordinates produced invalid GraphQL and failed with:

Field "currentLocationCoordinates" of type "Location" must have a selection of subfields

Hit in production by the Driver app agent on 2026-08-03 — the agent concluded lat/lng was unavailable and reported that to the user.

Fix

• Location signal names are read from the parsed GraphQL schema at override time (SignalCollection fields typed SignalLocation), so regenerated signals are picked up automatically.
• Both selection templates branch on those names and emit { latitude longitude hdop } subfield selections.
• Tool descriptions now document location support and the LocationAggregation set (AVG, RAND, FIRST, LAST).

Tests

• Unit: rendered queries for location+float mixes now validate against the real schema with gqlparser's validator (parse-only checks could not catch this class of bug).
• E2E: location signal inserted into ClickHouse; both tools round-trip coordinates. Verified failing before the fix with the exact production errors.

🤖 Generated with Claude Code

https://claude.ai/code/session_015hwzo7z9hmuqgJ2SHPusac