LECTURE STRUCTURELLE

Les anomalies

Les règles à seuils fixes qui lisent la collecte officielle — des faits mesurés, pas des prédictions.

Vigie — Anomaly beacon (structural reading) v0.1

Date: 2026-09-19 Method id: anomaly-beacon-v1 Code: scripts/compile_anomalies.py · Store: data/anomalies/latest_verdict.json

What this is

A finite catalogue of fixed-threshold rules measured over the City's own official roadworks collection. An anomaly is a counted collection fact — « the City declared 3 new obstructions on this street in one collection » — never a prediction, never an importance judgment, never a model output.

The beacon renders inside the Travaux et entraves section only, never in the first viewport (DESIGN.md). With zero measured anomalies the brief is byte-identical to a brief without the feature.

Rule catalogue (falsifiable)

All rules group entries by street_key (edge-atlas-v1 normalization). One entry naming several streets counts once per street. Counts are exact; evidence lists are capped at 8 ids.

id	Label	Fires when	Claim wording (French)
`poussee-declarations`	Poussée de déclarations	≥ 3 events new in this collection (diff `new`) share a street	« N nouvelles entraves déclarées sur X dans cette même collecte. »
`fin-reportee`	Fins reportées	≥ 2 events on a street carry the City's own `end_date_moved: later` revision (diff `changed`)	« La Ville a reporté la fin déclarée de N entraves sur X depuis la dernière collecte. »
`concentration`	Concentration	a street carries ≥ 8 active declarations and ≥ 4× the network median (median over streets with ≥ 1 active event)	« X compte N entraves actives déclarées ; médiane observée par rue sur le réseau : M (rapport R). »
`fenetre-depassee`	Fenêtre officielle dépassée	≥ 3 events on a street remain declared while their official `end_date` precedes the collection stamp	« N entraves sur X restent déclarées alors que leur fenêtre officielle est dépassée. »

Ratios and medians render in French notation (comma decimal, one digit).

Honesty rules

fin-reportee relays the City's own revision direction, literally.

Postponed ≠ extended works; the beacon never concludes anything.

fenetre-depassee measures the feed against itself. It never claims the

works ended, nor that the City is wrong; the official map stays the authority.

Diff-based rules require has_previous: a first collection never implies a

comparison that did not happen.

Every verdict row carries rule_id, thresholds, exact count, capped

evidence_event_ids, and status: proposed.

Verdict rows are capped at 6 (sorted by rule rank, then count descending,

then street key); the brief shows at most 3. anomaly_count stays exact.

Determinism and fail-soft

No wall clock: compiled_at is the collection stamp; a render-only rebuild

is byte-identical.

Absent, corrupt or foreign-method roadworks store → empty verdict

(has_store: false), exit 0. The edition never depends on the beacon.

The renderer re-validates the method string and the claim presence: a

foreign or empty verdict renders zero HTML.

Amendment path

Adding, removing or re-thresholding a rule means amending this file first; the test suite locks the code catalogue against this table (same lockstep discipline as ranking.md ↔ score_item and FACETS.md ↔ life_facets).

Kill list

Predictive or probabilistic anomaly « scores »
Anomaly visibility leaking into rank_score or the morning twin
Alert chrome: red banners, pulses, sirens, push notifications
Anomaly rules over article data (the beacon reads the official feed only)

Decision log

Date	Decision	Owner
2026-09-19	Ship v0.1 four-rule catalogue; beacon inside Travaux section only	Bucky + le porteur