Problem

On the analytics dataset query path (POST /api/v1/analytics/dataset/query), a metric widget filtered on a boolean field (e.g. { is_critical: true }) always returned 0, and pie/donut/bar charts grouped by a boolean dimension failed to bucket.

Root cause

A lossy string roundtrip in the filter normalizer:

1. stringifyForCube serialized boolean true → '1' (filter-normalizer.ts) — indistinguishable from a numeric 1.
2. ObjectQLStrategy then coerced '1' back to the number 1 via coerceFilterValueForSql and passed { is_critical: 1 } into engine.aggregate.
3. The stored field holds a real boolean true, so 1 !== true — the comparison never matched.

The SQL strategy needs 1/0 (better-sqlite3 cannot bind a JS boolean), but the ObjectQL engine compares against the stored runtime type — sharing one coercer was the defect.

Fix

• stringifyForCube serializes booleans as the tokens 'true'/'false', preserving boolean identity through the string[] pipeline form (SQL output unchanged: 'true' → 1).
• New coerceFilterValueForObjectQL recovers a real true/false for the ObjectQL engine; SQL path keeps recovering 1/0. Shared numeric recovery extracted into recoverNumber.
• ObjectQLStrategy.convertFilter uses the ObjectQL coercer.

Test

New objectql-strategy-boolean-filter.test.ts — the mock engine filters/buckets in-memory rows by strict === (so a stringified 1 fails it):

• { is_critical: true } → real boolean reaches the engine, count is non-zero (3);
• { is_critical: false } → matches its rows (2);
• group-by on a boolean dimension → produces both true (3) and false (2) buckets.

Full service-analytics suite (154 tests) passes; package builds clean.

Context: discovered while building an ObjectStack dashboard; the downstream project worked around it with a numeric-range filter + string mirror field. This is the real fix in framework.