Research Agent Concatenates Multiple Sources Under One Citation ID — And No Validator Catches It
The downstream symptom (orphan `[^N]` markers in exported memos) is a citation-format failure at the very top of the pipeline: `research_enhanced.py` writes multiple sources onto a single line under the same `[^N]:` heading, with no newline separators and frequent ID reuse. Six of nine research files in the Panthalassa-Deck-Series-B v0.0.3 run carry these malformed lines (one section reuses `[^12]` six times). The downstream regex parsers only see the first source per ID and silently drop the rest. The `citation_validator` agent that exists checks claim accuracy, not bibliography format, so the malformation passes through unflagged. The architectural fix is the Source Harvester / Section Writer split documented in CLAUDE.md §'Architectural direction (2026-05)' but not yet built. Three smaller backstops can close the gap before that ships.