worldmonitor/todos/175-pending-p2-region-taxonomy-3-sources-of-truth.md

status, priority, issue_id, tags, dependencies

status	priority	issue_id	tags	dependencies
pending	p2	175	code-review phase-0 regional-intelligence dry taxonomy

Region taxonomy has 3 independent sources of truth (PR #2942 should import REGIONS from geography.js)

Problem Statement

PR #2940 ships shared/geography.js with REGIONS and forecastLabel fields. PR #2942 ships ForecastPanel.ts:10-19 with a hardcoded FORECAST_REGIONS constant duplicating the same labels. Plus api/mcp.ts:556 enumerates DIFFERENT region examples ("Asia Pacific" not "East Asia"), breaking agent-native parity. Plus scripts/seed-forecasts.mjs writes f.region strings via MACRO_REGION_MAP that are a fourth implicit source.

Adding a region requires editing 3-4 files. They will drift.

Findings

• src/components/ForecastPanel.ts:10-19 — hardcoded FORECAST_REGIONS constant.
• shared/geography.js:46-124 — canonical REGIONS with forecastLabel field.
• api/mcp.ts:556-577 — generate_forecasts tool description enumerates "Asia Pacific" etc. (different from geography).
• scripts/seed-forecasts.mjs — MACRO_REGION_MAP as implicit fourth source.

Proposed Solutions

Option 1: ForecastPanel.ts imports REGIONS from shared/geography

Derive FORECAST_REGIONS via REGIONS.map(r => ({ id: r.id, label: r.forecastLabel })). Update api/mcp.ts to enumerate the same labels (also via import from geography).

Pros: Zero new files; uses the module already designated as canonical; straight deletion of duplicates. Cons: Minor — TS consumers need to deal with a .js import, but that's already a pattern elsewhere. Effort: Small. Risk: Low.

Option 2: Extract a shared/forecast-regions.ts module

Create a dedicated shared/forecast-regions.ts module exporting the canonical list. ForecastPanel + MCP both import.

Pros: Explicit module for this concern. Cons: Creates a second layer of indirection when geography.js is already the intended source of truth. Effort: Small. Risk: Low.

Recommended Action

Option 1 — geography.js is already the canonical source; the panel and MCP description should consume it directly. Delete FORECAST_REGIONS and the ad-hoc MCP examples.

Technical Details

shared/geography.js already has the forecastLabel field on every REGIONS entry specifically for this use case (added in PR #2940). The panel duplication in #2942 defeats the purpose. The MCP description drift ("Asia Pacific" vs "East Asia") is an agent-native correctness bug — MCP clients generate structured calls against the documented examples, so mismatched labels become unresolvable filters at runtime.

The scripts/seed-forecasts.mjs MACRO_REGION_MAP is a fourth source but its job is ISO2 → region mapping, not label authority. It should still derive its region IDs from REGIONS.

Acceptance Criteria

• ForecastPanel.ts imports REGIONS from shared/geography.js.
• api/mcp.ts generate_forecasts tool description enumerates exactly the same labels.
• Adding a region in geography.js automatically updates UI pills and MCP description.
• MACRO_REGION_MAP in seed-forecasts.mjs references REGIONS for the region IDs.

Work Log

Resources

• PR #2940
• PR #2942
• Spec: docs/internal/pro-regional-intelligence-upgrade.md