---
session: ses_2bed
updated: 2026-03-31T00:07:06.270Z
---

# Session Summary

## Goal
Generate and update the project's mindmodel, then debug why the trajectories plot is not showing in the Explorer app.

## Constraints & Preferences
- Keep changes minimal and reversible
- Diagnostics must be opt-in (EXPLORER_DEBUG_TRAJECTORIES env var)
- Helpers must be import-safe and pure
- Use `uv` for local/CI runs (not pip directly)
- Follow existing project conventions (snake_case, PascalCase for classes, dataclass Config)

## Progress
### Done
- [x] **Generated mindmodel** via `mm-constraint-writer` agent → wrote 9 files to `.mindmodel/`:
  - `manifest.yaml`, `stack/stack.yaml`, `architecture/architecture.yaml`, `conventions/conventions.yaml`, `domain/domain-glossary.yaml`, `patterns/patterns.yaml`, `anti-patterns/anti-patterns.yaml`, `dependencies/dependencies.yaml`, `constraints/README.md`
  - Top anti-pattern: `explorer_helpers.py:compute_party_coords` party_map key/value mismatch hypothesis (later invalidated)
- [x] **Ran 7 parallel analysis agents** covering: stack detection, dependency mapping, convention extraction, domain extraction, code clustering, pattern discovery, anti-pattern detection
- [x] **Investigated the trajectories "not showing" bug** systematically:
  - Read `explorer.py` (2948 lines), `explorer_helpers.py` (297 lines), `analysis/political_axis.py` (695 lines), `analysis/trajectory.py` (297 lines), `analysis/visualize.py`, `scripts/diagnose_trajectories_cli.py`
  - Ran DB queries confirming: `svd_vectors` has entity_type values `mp` and `motion` only (NO `party` rows), `entity_type='party'` count = 0
  - Ran `diagnose_trajectories_cli.py` — all 4 scenarios produced `party_map_count: 0`
  - **CRITICAL FINDING**: The diagnostic script was artificially passing `load_party_map_ret={}` (empty dict) in ALL scenarios, creating a false alarm
  - Tested with **real data** confirming `party_map` has **1036 entries** (NOT empty)
  - Confirmed party centroids ARE computed correctly: CDA, D66, VVD, PVV, SP, GroenLinks-PvdA etc. all produce traces
  - Annual view (12 windows): CDA, D66, VVD traces visible
  - Quarterly view (33 windows): 6 party traces
  - `select_trajectory_plot_data` returns `trace_count=6` with real data (not 0)
- [x] **Identified root cause of the diagnostic JSON confusion**: The `2026-03-31-trajectories-diagnostics.json` was created by `diagnose_trajectories_cli.py` which passes `load_party_map_ret={}` artificially, not reflecting real production behavior

## Key Decisions
- **The trajectories plot DOES work correctly**: The diagnostic JSON showing `party_map_count: 0` was caused by the diagnostic script itself (passing empty party_map), NOT a production bug
- **No production code changes needed for the core trajectories functionality** — it's working as designed
- **The diagnostic script `scripts/diagnose_trajectories_cli.py` needs fixing** to use real data paths instead of mocking everything to empty
- **The anti-pattern detected** (`compute_party_coords` party_map mismatch) was a false alarm — entity_ids in `svd_vectors` are ALL MP names, never party names (no `entity_type='party'` rows exist)

## Next Steps
1. **Fix `scripts/diagnose_trajectories_cli.py`** to use real data paths (`data/motions.db`) and real `load_party_map` / `load_positions` calls instead of mocking everything to empty
2. **Re-run the fixed diagnostic script** to produce a correct `trajectories-diagnostics.json` artifact
3. **Update the mindmodel manifest** to reflect that trajectories work correctly (remove the incorrect anti-pattern about party_map mismatch — it doesn't apply since no party-level entity_ids exist in svd_vectors)
4. **Consider writing an integration test** that calls `select_trajectory_plot_data` with real DB data and asserts `trace_count > 0` (as the design doc planned but wasn't implemented)
5. **Decide what to do with `EXPLORER_FORCE_SHOW_TRAJECTORIES=1`** — currently a no-op because party centroids always compute; could be useful for debugging or removed as dead code

## Critical Context
- **Project type**: Dutch political voting compass (Stemwijzer), Python ≥3.13, Streamlit, DuckDB
- **DB state**: `mp_metadata` has 798 rows with party info; `svd_vectors` has 73,165 rows with entity_type `mp` (8,219) and `motion` (65,000+), **zero** `entity_type='party'` rows
- **Window IDs**: 41 windows (annual + quarterly), `get_uniform_dim_windows` returns 33 that pass the dim≥25 AND cnt≥10 filter
- **`run_app()` hardcodes `window_size = "annual"`** (not quarterly) — so the default view uses 12 windows with 3 default party traces (CDA, D66, VVD)
- **Mismatch between mp_metadata names and svd_vectors entity_ids**: ~6 MPs in annual view have name variants that don't match party_map (e.g., `De Pater-Postma, W.L.` vs `Pater-Postma de, W.L.`), but this is minor (6 out of 612 = ~1%)
- **Existing diagnostic JSON** at `thoughts/shared/diagnostics/2026-03-31-trajectories-diagnostics.json` shows `party_map_count: 0` — this is a red herring from the diagnostic script, NOT real production behavior

## File Operations

### Read
- `/home/sgeboers/Projects/stemwijzer/.mindmodel/manifest.yaml`
- `/home/sgeboers/Projects/stemwijzer/explorer.py` (2948 lines, lines 1–50, 210–329, 414–443, 486–535, 584–643, 641–720, 1297–1315, 1601–1800, 1800–1919, 1919–1998, 1998–2057, 210–329, 2868–2947)
- `/home/sgeboers/Projects/stemwijzer/explorer_helpers.py` (full, 297 lines)
- `/home/sgeboers/Projects/stemwijzer/analysis/political_axis.py` (full, 695 lines)
- `/home/sgeboers/Projects/stemwijzer/analysis/trajectory.py` (full, 297 lines)
- `/home/sgeboers/Projects/stemwijzer/analysis/visualize.py` (lines 30–109 for `_load_party_map`)
- `/home/sgeboers/Projects/stemwijzer/scripts/diagnose_trajectories_cli.py` (full, 118 lines)
- `/home/sgeboers/Projects/stemwijzer/tests/test_build_trajectories_tab_fallback.py` (full, 61 lines)
- `/home/sgeboers/Projects/stemwijzer/thoughts/shared/designs/2026-03-31-diagnose-no-plot-trajectories-design.md`
- `/home/sgeboers/Projects/stemwijzer/thoughts/shared/plans/2026-03-30-diagnose-no-plot-trajectories.md`

### Modified
- (none yet — verified trajectories work correctly via DB queries and Python tests)