From 1f47c17f5b406dd6527087418baf8097a18e682c Mon Sep 17 00:00:00 2001
From: Neal006 <nealdaftary0405@gmail.com>
Date: Sun, 13 Sep 2026 06:15:37 +0530
Subject: [PATCH] feat(WP3): vehicle form, observation guard, asap bays, done
 events, queue with move-by

- POST /sessions accepts vehicle{model,battery_kwh,max_kw}, soc_now,
  target_soc: kwh_needed = (target - now) * battery; need_confidence
  declared | history (bay median) | site (day median) replaces the 8.0 default.
  car() plans with min(bay, car); the sim draws min(limit, car_kw * taper).
- Observation guard: 5 min under 80 % of the limit (not tapering) -> max_kw =
  metered * 1.05 for the session, event cap_observed.
- site.json connectors_asap [c41, c42]: those bays are always ASAP.
- Sim.tick emits done (+ idle_since); Sim.waiting holds arrivals with no bay
  and plugs them FIFO as bays free; a done car idle >= 10 min is unplugged
  when someone waits (assumption A5). resolve() gives the slackest plugged
  cars a move-by deadline (now + e_rem / p_max), one per waiting car, never
  urgent or < 1 h slack; event move_by. /demo/oversubscribe queues instead
  of dropping.
- Additive contract: SessionOut/ConnectorMeter/MeterMsg/StatusOut fields,
  EventMsg names done | cap_observed | move_by. Contract files regenerated.
- 5 new tests (69): 3.3 kW car planned at 3.3 and full by its deadline;
  need from history/site; guard trips and the plan follows; asap bay at
  full power with 8 h slack; queue of 60 late cars tightens the slackest,
  waiting cars get bays, done events fire. smoke OK; prove unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017thvbGo7rTVnG2f46cLMzU
---
 AGENTS.md            |   9 ++--
 data/site.json       |   2 +-
 docs/openapi.json    | 117 +++++++++++++++++++++++++++++++++++++++++++
 docs/ws-frames.json  |  50 ++++++++++++++++++
 noonshift/api.py     | 112 +++++++++++++++++++++++++++++++++++------
 noonshift/models.py  |  27 +++++++++-
 noonshift/sim.py     |  27 +++++++---
 scripts/smoke.py     |  15 +++++-
 tests/data/site.json |   2 +-
 tests/test_day.py    |  89 ++++++++++++++++++++++++++++++++
 10 files changed, 421 insertions(+), 29 deletions(-)

diff --git a/AGENTS.md b/AGENTS.md
index f0a194c..1bd2bed 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -7,7 +7,7 @@ Hackathon entry: "Noonshift" — a CPO-side, deadline-based EV charging schedule
 ## Stack & Commands
 - Python 3.12/3.13 · FastAPI · scipy 1.14 (HiGHS LP) · mobilityhouse/ocpp · asyncpg/Postgres (optional) · Docker Compose. Two Vite front-ends: `web/` (ops dashboard, React+JSX+Tailwind 3, :5173) and `wattwise/` (driver app, React+TS+Tailwind 4, :5174); `npm install && npm run dev` in each, both proxy `/api` and `/ws` to :8000. `npm run build` in each, then `docker compose up` serves them on :3000 / :3001.
 - `python -m venv .venv && .venv/Scripts/pip install -r requirements-dev.txt`
-- `python -m pytest` (63 tests, ~60 s) · `python scripts/prove.py` (slide 1) · `python -m noonshift.test_loop` · `docker compose up -d --build`
+- `python -m pytest` (69 tests, ~90 s) · `python scripts/prove.py` (slide 1) · `python -m noonshift.test_loop` · `docker compose up -d --build`
 - Data: `python -m noonshift.seed gen` (placeholders) · `python scripts/fetch_data.py signal|caiso|sessions --day ...` (real).
 
 ## Current State & Focus
@@ -25,9 +25,9 @@ Signals (WattTime MOER; CAISO fuel-mix fallback) + tariff table + sessions (dead
 
 ## File Map
 - `noonshift/scheduler.py` — `solve(cars, site, signal, tariff, now)`, `solve_lp()` (+info), `impact()`, `impact_detail()`, `price(slack, *, r, saving_usd, kwh, alpha, urgent)` (§7b: R − α·S/E, ≤ R), `tier_of()`; per-car optional `floor_alpha`, `priority`; constants W_CARBON, ALPHA, FLOOR_EVERY, FIRST_HOUR_KWH (3.5), SPRINT_SLOTS, BUFFER_COST, M_SHORT, M_FLOOR, ASAP_EPS, E_MIN, MIN_KW. Slot 0 carries only its remaining minutes (`dur[0]`); floor checkpoints are times since arrival, pro rata in the slot containing the mark.
-- `noonshift/api.py` — FastAPI app, state dict `S`, `resolve()`, `step()`, `session_impact()`, `meter_history()`, ladder `pick_mode()`, `/demo/*`; `POST /sessions/{id}/urgency {level: now|soon|priority, leave_at?}` (`/boost` = alias of `now`; `URGENCY_MIN` 15 min; `PRIORITY` = floor 0.9 / weight 2.0); `site_rate()` = `site.json: employee_rate_usd_per_kwh` (0 = free); `session_price()`.
-- `noonshift/sim.py` — `Sim`, `Connector(id, p_max_kw, safe_kw)` (taper from 80% SoC; plug-in starts on `safe_kw`; a `set_limit` expires after `DYN_VALID_MIN`=15 min back to `safe_kw`), `load_sessions()`, `safe_share_kw(site)` = min(p_max, (feed − max building)/n) = 1.833 kW on site-1.
-- `noonshift/models.py` — pydantic REST bodies + WS frames (contract with front-end). `SignalHour` added for `GET /grid/signal` (hourly MOER g/kWh + $/kWh; frames unchanged).
+- `noonshift/api.py` — FastAPI app, state dict `S`, `resolve()`, `step()`, `session_impact()`, `meter_history()`, ladder `pick_mode()`, `/demo/*`; `POST /sessions/{id}/urgency {level: now|soon|priority, leave_at?}` (`/boost` = alias of `now`; `URGENCY_MIN` 15 min; `PRIORITY` = floor 0.9 / weight 2.0); `site_rate()` = `site.json: employee_rate_usd_per_kwh` (0 = free); `session_price()`; `car_kw(c)` = min(bay, `session.max_kw`); `need_estimate()` (bay history median → site median); `observe_caps()` (5 min under 80 % of limit → `max_kw` = metered × 1.05, event `cap_observed`); `move_by()` (waiting cars → slackest plugged cars get deadline = now + e_rem/p_max, one per waiting car); `site.json: connectors_asap` bays are always `boost`.
+- `noonshift/sim.py` — `Sim`, `Connector(id, p_max_kw, safe_kw)` (taper from 80% SoC; plug-in starts on `safe_kw`; a `set_limit` expires after `DYN_VALID_MIN`=15 min back to `safe_kw`), `load_sessions()`, `safe_share_kw(site)` = min(p_max, (feed − max building)/n) = 1.833 kW on site-1. `Sim.waiting` (arrivals with no bay; plugged FIFO as bays free); a `done` car with `idle_since` ≥ `MOVE_AFTER_MIN`=10 is unplugged when someone waits (A5); `session.car_kw` = the car's physical limit (sim only; `max_kw` is the planner's belief).
+- `noonshift/models.py` — pydantic REST bodies + WS frames (contract with front-end). `SessionIn` optional `vehicle{model,battery_kwh,max_kw}`, `soc_now`, `target_soc`; `SessionOut` +`kwh_needed`, `need_confidence`, `max_kw`, `urgency`; `ConnectorMeter` +`idle_min`, `need_confidence`, `p_max_kw`, `cap_observed`, `asap`, `move_by`, `urgency`; `MeterMsg.waiting`; `StatusOut` +`safe_share_kw`, `waiting`, `connectors_asap`; `EventMsg.name` +`urgency|done|cap_observed|move_by`. All additive.
 - `web/src/context/GlobalStateContext.jsx` — ops app state: opens `/ws`, polls `/sites/site-1/impact|status`, derives the page shape (siteDetail/connectors Gantt on a 06–22 axis, sessions, alerts from events, chargersList); `triggerEvent()` maps demo buttons → `/demo/*`, prioritize → `/sessions/{id}/boost`.
 - `.docs/ROADMAP.md` — plain-language plan (§0 status, §1 driver inputs, §3 emergency rules, §4 price flip, §5 evidence runs, §7 CI, §8 order). `.github/workflows/ci.yml` — backend job + web/wattwise matrix.
 - `wattwise/src/api/noonshift.ts` — driver app client + hand-copied types; `connectWs()`, `onSimDay()` (ready-by is built on the **sim** day and must be > sim now).
@@ -79,6 +79,7 @@ Signals (WattTime MOER; CAISO fuel-mix fallback) + tariff table + sessions (dead
 - 2026-09-12 — Session data = ACN 2019-04-09 re-dated onto the 2026 signal day; kwh_needed = delivered energy, stated departure = the driver's own input (early leavers kept).
 
 ## Changelog
+2026-09-13 | WP3 cars, needs, queues | models.py, sim.py, api.py, data/site.json, tests/test_day.py, scripts/smoke.py | vehicle form → per-car cap + kWh from SoC; observation guard believes the meter; connectors_asap c41/c42; done event + idle_min; Sim.waiting + move-by tightening; a notified done car moves within 10 min when someone waits
 2026-09-13 | WP2 fail-safe an inspector accepts: static share under everything | sim.py, api.py, scheduler.py, ocpp_gateway.py, models.py, data/site.json, tests/test_day.py | `full` rung, `apply_limits` fallback and the linprog fallback all return `safe_share_kw`; kill-the-loop test: 6 h with no step() never exceeds headroom and after 15 min never exceeds n × share; `StatusOut.safe_share_kw`
 2026-09-13 | WP1 pricing + emergency + first-hour floor | scheduler.py, api.py, models.py, data/site.json, tests/, scripts/smoke.py, .docs/implementation-plan.md | price() = §7b shared savings (never above R); urgency endpoint; slot-0 remaining-duration + time-anchored checkpoints fixed a lost-energy bug that the 3.5 kWh promise exposed
 2026-09-13 | Open-source docs pass: README rewrite (Mermaid, quick start, results, OCPP 1.6J badge), LICENSE/CONTRIBUTING/CODE_OF_CONDUCT/SECURITY/CHANGELOG, issue+PR templates, .docs/ARCHITECTURE.md (6 validated diagrams), .docs/README.md index; all human docs moved to .docs/; business.md (break points, §4b emergency scale at R, §7b shared-savings formula), metrics.md, solutions.md (real-world fixes → code; drivers under-state stay 29/36; prove.py plans with perfect foresight) | README.md, .docs/, LICENSE, CONTRIBUTING.md, SECURITY.md, CHANGELOG.md, .github/ | All Mermaid blocks validated with mermaid@11 + jsdom; ROADMAP emergency pricing reconciled to "R, no quota".
diff --git a/data/site.json b/data/site.json
index c020fa9..07429ec 100644
--- a/data/site.json
+++ b/data/site.json
@@ -1 +1 @@
-{"id": "site-1", "feed_kw": 150, "block_kw": 100, "connectors": ["c01", "c02", "c03", "c04", "c05", "c06", "c07", "c08", "c09", "c10", "c11", "c12", "c13", "c14", "c15", "c16", "c17", "c18", "c19", "c20", "c21", "c22", "c23", "c24", "c25", "c26", "c27", "c28", "c29", "c30", "c31", "c32", "c33", "c34", "c35", "c36", "c37", "c38", "c39", "c40", "c41", "c42", "c43", "c44", "c45", "c46", "c47", "c48", "c49", "c50", "c51", "c52", "c53", "c54", "c55", "c56", "c57", "c58", "c59", "c60"], "p_max_kw": 7.0, "building_load_kw": [20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 21.7, 23.3, 25.0, 26.7, 28.3, 30.0, 31.7, 33.3, 35.0, 36.7, 38.3, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 38.3, 36.7, 35.0, 33.3, 31.7, 30.0, 28.3, 26.7, 25.0, 23.3, 21.7, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0], "employee_rate_usd_per_kwh": 0.25, "driver_share": 0.5, "noonshift_share": 0.2, "safe_share_kw": 1.833}
\ No newline at end of file
+{"id": "site-1", "feed_kw": 150, "block_kw": 100, "connectors": ["c01", "c02", "c03", "c04", "c05", "c06", "c07", "c08", "c09", "c10", "c11", "c12", "c13", "c14", "c15", "c16", "c17", "c18", "c19", "c20", "c21", "c22", "c23", "c24", "c25", "c26", "c27", "c28", "c29", "c30", "c31", "c32", "c33", "c34", "c35", "c36", "c37", "c38", "c39", "c40", "c41", "c42", "c43", "c44", "c45", "c46", "c47", "c48", "c49", "c50", "c51", "c52", "c53", "c54", "c55", "c56", "c57", "c58", "c59", "c60"], "p_max_kw": 7.0, "building_load_kw": [20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 21.7, 23.3, 25.0, 26.7, 28.3, 30.0, 31.7, 33.3, 35.0, 36.7, 38.3, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 38.3, 36.7, 35.0, 33.3, 31.7, 30.0, 28.3, 26.7, 25.0, 23.3, 21.7, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0], "employee_rate_usd_per_kwh": 0.25, "driver_share": 0.5, "noonshift_share": 0.2, "safe_share_kw": 1.833, "connectors_asap": ["c41", "c42"]}
\ No newline at end of file
diff --git a/docs/openapi.json b/docs/openapi.json
index bf004d6..627c939 100644
--- a/docs/openapi.json
+++ b/docs/openapi.json
@@ -1022,6 +1022,36 @@
        }
       ],
       "title": "Kwh Needed"
+     },
+     "vehicle": {
+      "anyOf": [
+       {
+        "$ref": "#/components/schemas/Vehicle"
+       },
+       {
+        "type": "null"
+       }
+      ]
+     },
+     "soc_now": {
+      "anyOf": [
+       {
+        "type": "number",
+        "maximum": 1.0,
+        "minimum": 0.0
+       },
+       {
+        "type": "null"
+       }
+      ],
+      "title": "Soc Now"
+     },
+     "target_soc": {
+      "type": "number",
+      "maximum": 1.0,
+      "exclusiveMinimum": 0.0,
+      "title": "Target Soc",
+      "default": 1.0
      }
     },
     "type": "object",
@@ -1088,6 +1118,38 @@
        }
       ],
       "title": "Urgency"
+     },
+     "kwh_needed": {
+      "type": "number",
+      "title": "Kwh Needed",
+      "default": 0.0
+     },
+     "need_confidence": {
+      "anyOf": [
+       {
+        "type": "string",
+        "enum": [
+         "declared",
+         "history",
+         "site"
+        ]
+       },
+       {
+        "type": "null"
+       }
+      ],
+      "title": "Need Confidence"
+     },
+     "max_kw": {
+      "anyOf": [
+       {
+        "type": "number"
+       },
+       {
+        "type": "null"
+       }
+      ],
+      "title": "Max Kw"
      }
     },
     "type": "object",
@@ -1189,6 +1251,19 @@
       "type": "number",
       "title": "Safe Share Kw",
       "default": 0.0
+     },
+     "waiting": {
+      "type": "integer",
+      "title": "Waiting",
+      "default": 0
+     },
+     "connectors_asap": {
+      "items": {
+       "type": "string"
+      },
+      "type": "array",
+      "title": "Connectors Asap",
+      "default": []
      }
     },
     "type": "object",
@@ -1261,6 +1336,48 @@
      "type"
     ],
     "title": "ValidationError"
+   },
+   "Vehicle": {
+    "properties": {
+     "model": {
+      "anyOf": [
+       {
+        "type": "string"
+       },
+       {
+        "type": "null"
+       }
+      ],
+      "title": "Model"
+     },
+     "battery_kwh": {
+      "anyOf": [
+       {
+        "type": "number",
+        "exclusiveMinimum": 0.0
+       },
+       {
+        "type": "null"
+       }
+      ],
+      "title": "Battery Kwh"
+     },
+     "max_kw": {
+      "anyOf": [
+       {
+        "type": "number",
+        "exclusiveMinimum": 0.0
+       },
+       {
+        "type": "null"
+       }
+      ],
+      "title": "Max Kw"
+     }
+    },
+    "type": "object",
+    "title": "Vehicle",
+    "description": "What the driver tells us about the car. All optional: the brain plans with the bay's limit when it knows nothing."
    }
   }
  }
diff --git a/docs/ws-frames.json b/docs/ws-frames.json
index 2a7fd19..199d63b 100644
--- a/docs/ws-frames.json
+++ b/docs/ws-frames.json
@@ -70,6 +70,48 @@
      ],
      "default": null,
      "title": "Urgency"
+    },
+    "idle_min": {
+     "default": 0,
+     "title": "Idle Min",
+     "type": "integer"
+    },
+    "need_confidence": {
+     "anyOf": [
+      {
+       "enum": [
+        "declared",
+        "history",
+        "site"
+       ],
+       "type": "string"
+      },
+      {
+       "type": "null"
+      }
+     ],
+     "default": null,
+     "title": "Need Confidence"
+    },
+    "p_max_kw": {
+     "default": 0.0,
+     "title": "P Max Kw",
+     "type": "number"
+    },
+    "cap_observed": {
+     "default": false,
+     "title": "Cap Observed",
+     "type": "boolean"
+    },
+    "asap": {
+     "default": false,
+     "title": "Asap",
+     "type": "boolean"
+    },
+    "move_by": {
+     "default": false,
+     "title": "Move By",
+     "type": "boolean"
     }
    },
    "required": [
@@ -131,6 +173,9 @@
       "deadline",
       "boost",
       "urgency",
+      "done",
+      "cap_observed",
+      "move_by",
       "dr",
       "demo",
       "mode",
@@ -195,6 +240,11 @@
      },
      "title": "Connectors",
      "type": "array"
+    },
+    "waiting": {
+     "default": 0,
+     "title": "Waiting",
+     "type": "integer"
     }
    },
    "required": [
diff --git a/noonshift/api.py b/noonshift/api.py
index 603f5fa..6877b6e 100644
--- a/noonshift/api.py
+++ b/noonshift/api.py
@@ -7,6 +7,7 @@
 import json
 import os
 import random
+import statistics
 from datetime import datetime, timedelta
 
 from fastapi import FastAPI, HTTPException, Query, WebSocket, WebSocketDisconnect
@@ -55,13 +56,75 @@ def pick_mode(now):
 PRIORITY = {"floor_alpha": 0.9, "priority": 2.0}  # business.md §4b low band: floor 90 % pro-rata, gives way last
 
 
+OBS_MIN = 5          # observation guard: minutes at a limit before the meter is believed over the form
+OBS_FRAC = 0.8       # ... when the car draws less than this share of its limit
+OBS_MARGIN = 1.05    # the new planning cap: metered kW plus a little, so a warming battery can still climb
+
+
+def car_kw(c):
+    """What the brain plans with for this car: the bay's limit, capped by the vehicle form or the observation guard."""
+    return min(c.p_max_kw, c.session.get("max_kw") or c.p_max_kw)
+
+
 def car(c):
     s = c.session
     return {"connector_id": c.id, "arrival": s["arrival"], "departure": s["user_stated_departure"],
-            "kwh_needed": s["kwh_needed"], "kwh_delivered": s["kwh_delivered"], "p_max_kw": c.p_max_kw, "boost": s["boost"],
+            "kwh_needed": s["kwh_needed"], "kwh_delivered": s["kwh_delivered"], "p_max_kw": car_kw(c),
+            "boost": s["boost"] or c.id in S["site"].get("connectors_asap", []),  # fleet bays are never deferred
             **(PRIORITY if s.get("urgency") == "priority" else {})}
 
 
+def need_estimate(connector_id):
+    """solutions.md §11: no form and no number from the driver -> this bay's history, else the site's median."""
+    ss = S["sim"].sessions.values()
+    here = [s["kwh_needed"] for s in ss if s["connector_id"] == connector_id and s["status"] == "ended"]
+    if here:
+        return round(statistics.median(here), 1), "history"
+    return round(statistics.median(s["kwh_needed"] for s in ss), 1), "site"
+
+
+def observe_caps():
+    """The observation guard (solutions.md §10): a car that has drawn < OBS_FRAC of its limit for OBS_MIN minutes cannot
+    take what we plan for it (PHEV, cold battery, wrong form). Believe the meter: cap it at metered * OBS_MARGIN for the
+    rest of the session. Skipped once the car is tapering (> 80 % of its need), which is not a cap but physics."""
+    out = []
+    for c in S["sim"].active():
+        s = c.session
+        slow = s["status"] == "charging" and c.kw > 0 and c.kw < OBS_FRAC * c.limit_kw and s["kwh_delivered"] < 0.8 * s["kwh_needed"]
+        c.slow_min = c.slow_min + 1 if slow and not s.get("cap_observed") else 0
+        if c.slow_min >= OBS_MIN:
+            s["max_kw"], s["cap_observed"], c.slow_min = round(c.kw * OBS_MARGIN, 2), True, 0
+            out.append({"name": "cap_observed", "session_id": s["id"], "connector_id": c.id, "limit_kw": round(c.limit_kw, 2),
+                        "metered_kw": round(c.kw, 2), "max_kw": s["max_kw"]})
+    return out
+
+
+def move_by():
+    """solutions.md §3: cars are waiting, so the plugged cars with the most slack get a move-by time: deadline = now +
+    time to finish at full power. Never a car with < 1 h slack, never an urgent one, one tightened car per waiting car."""
+    sim = S["sim"]
+    now = sim.now
+    need = len(sim.waiting) - sum(1 for c in sim.active() if c.session.get("move_by"))
+    out = []
+    if need <= 0:
+        return out
+
+    def slack(c):
+        s = c.session
+        return (s["user_stated_departure"] - now).total_seconds() / 3600 - max(0.0, s["kwh_needed"] - s["kwh_delivered"]) / car_kw(c)
+
+    cands = sorted((c for c in sim.active() if c.status == "charging" and not c.session.get("urgent") and not c.session.get("move_by")
+                    and slack(c) >= 1.0), key=slack, reverse=True)
+    for c in cands[:need]:
+        s = c.session
+        was = s["user_stated_departure"]
+        finish = now + timedelta(hours=max(0.0, s["kwh_needed"] - s["kwh_delivered"]) / car_kw(c)) + SLOT
+        s["user_stated_departure"], s["move_by"] = finish.replace(second=0, microsecond=0), True
+        out.append({"name": "move_by", "session_id": s["id"], "connector_id": c.id, "deadline_was": was.isoformat(),
+                    "move_by": s["user_stated_departure"].isoformat(), "waiting": len(sim.waiting)})
+    return out
+
+
 def site_rate():
     """R: what the driver pays per kWh today. 0 = free workplace charging (business.md §0b)."""
     return float(S["site"].get("employee_rate_usd_per_kwh", 0.0))
@@ -142,6 +205,8 @@ async def resolve(reason):
     sim = S["sim"]
     now = sim.now
     mode = S["mode"] = pick_mode(now)
+    for e in move_by():
+        await event("move_by", e)
     cars = [car(c) for c in sim.active() if c.session["status"] == "charging"]
     site = {"feed_kw": S["site"]["feed_kw"], "block_kw": S["site"]["block_kw"], "safe_share_kw": safe_share_kw(S["site"]),
             "building_load_kw": aligned(S["site"]["building_load_kw"], now)}
@@ -174,6 +239,7 @@ async def resolve(reason):
 def meter_msg():
     sim = S["sim"]
     conns = []
+    asap = S["site"].get("connectors_asap", [])
     for c in sim.connectors.values():
         s = c.session
         conns.append(ConnectorMeter(
@@ -181,16 +247,20 @@ def meter_msg():
             status=c.status if s else "idle", kw=round(c.kw, 2),
             kwh_delivered=round(s["kwh_delivered"], 3) if s else 0, kwh_needed=s["kwh_needed"] if s else 0,
             departure_at=s["user_stated_departure"] if s else None, boost=s["boost"] if s else False,
-            urgency=s.get("urgency") if s else None))
+            urgency=s.get("urgency") if s else None,
+            idle_min=int((sim.now - s["idle_since"]).total_seconds() // 60) if s and s.get("idle_since") else 0,
+            need_confidence=s.get("need_confidence") if s else None, p_max_kw=car_kw(c) if s else c.p_max_kw,
+            cap_observed=bool(s.get("cap_observed")) if s else False, asap=c.id in asap,
+            move_by=bool(s.get("move_by")) if s else False))
     return MeterMsg(sim_time=sim.now, mode=S["mode"], site_kw=round(sum(c.kw for c in sim.connectors.values()), 2),
                     building_load_kw=S["site"]["building_load_kw"][slot_of(sim.now)], feed_kw=S["site"]["feed_kw"],
-                    connectors=conns)
+                    connectors=conns, waiting=len(sim.waiting))
 
 
 async def step():
     """One sim-minute: draw power, handle plug-ins/unplugs, re-solve on event or 5-min boundary, publish meters."""
     sim = S["sim"]
-    events = sim.tick(1)
+    events = sim.tick(1) + observe_caps()
     meter_history()
     for e in events:
         await event(e["name"], e)
@@ -227,12 +297,14 @@ def session_out(s):
             eta = h0 + k * SLOT
             break
         acc += v * 5 / 60
-    p_max = sim.connectors[s["connector_id"]].p_max_kw
+    c = sim.connectors.get(s["connector_id"])
+    p_max = car_kw(c) if c and c.session is s else min(sim.connectors[s["connector_id"]].p_max_kw, s.get("max_kw") or 99)
     slack = 0 if s["boost"] else (s["user_stated_departure"] - now).total_seconds() / 3600 - max(0, s["kwh_needed"] - s["kwh_delivered"]) / p_max
     return SessionOut(session_id=s["id"], connector_id=s["connector_id"], status=s["status"],
                       plan=PlanWindow(start=h0 + on[0] * SLOT if on else None, end=h0 + (on[-1] + 1) * SLOT if on else None,
                                       ready_by=s["user_stated_departure"]),
-                      eta=eta, price=session_price(s, slack), boost=s["boost"], urgency=s.get("urgency"))
+                      eta=eta, price=session_price(s, slack), boost=s["boost"], urgency=s.get("urgency"),
+                      kwh_needed=s["kwh_needed"], need_confidence=s.get("need_confidence"), max_kw=s.get("max_kw"))
 
 
 def get_session(sid):
@@ -287,19 +359,30 @@ async def create_session(body: SessionIn):
         raise HTTPException(404, "no such connector")
     if body.departure_at <= sim.now:
         raise HTTPException(400, f"departure_at must be after sim time {sim.now.isoformat()}")
+    v = body.vehicle
+    if v and v.battery_kwh and body.soc_now is not None:  # solutions.md §11: the form beats a typed number
+        kwh, conf = round(max(0.0, body.target_soc - body.soc_now) * v.battery_kwh, 2), "declared"
+    elif body.kwh_needed:
+        kwh, conf = body.kwh_needed, "declared"
+    else:
+        kwh, conf = need_estimate(c.id)
     if c.session:
         s = c.session
         s["user_stated_departure"] = body.departure_at
-        if body.kwh_needed:
-            s["kwh_needed"] = max(body.kwh_needed, s["kwh_delivered"])
+        if body.kwh_needed or (v and v.battery_kwh and body.soc_now is not None):
+            s["kwh_needed"], s["need_confidence"] = max(kwh, s["kwh_delivered"]), conf
         name = "deadline"
     else:
         S["next_id"] += 1
         s = {"id": S["next_id"], "connector_id": c.id, "arrival": sim.now, "departure": body.departure_at,
-             "user_stated_departure": body.departure_at, "kwh_needed": body.kwh_needed or 8.0,
+             "user_stated_departure": body.departure_at, "kwh_needed": kwh, "need_confidence": conf,
              "kwh_delivered": 0.0, "boost": False, "status": "pending", "ended_at": None}
         sim.arrive(s)
         name = "plug_in"
+    if v:
+        s["vehicle"] = v.model_dump(exclude_none=True)
+        if v.max_kw:
+            s["max_kw"] = s["car_kw"] = v.max_kw  # the planner's belief and, in the sim, the physical truth
     await event(name, {"session_id": s["id"], "connector_id": c.id, "departure_at": body.departure_at.isoformat()})
     await db.save_session(s)
     await resolve(name)
@@ -396,7 +479,8 @@ def site_status(site_id: str):
     return StatusOut(mode=S["mode"], last_solve_at=S["last_solve_at"],
                      connectors_active=sum(c.status == "charging" for c in S["sim"].active()),
                      feed_kw=S["site"]["feed_kw"], block_kw=S["site"]["block_kw"], sim_time=S["sim"].now,
-                     safe_share_kw=safe_share_kw(S["site"]))
+                     safe_share_kw=safe_share_kw(S["site"]), waiting=len(S["sim"].waiting),
+                     connectors_asap=S["site"].get("connectors_asap", []))
 
 
 @app.get("/price", response_model=PricePreview)
@@ -520,11 +604,11 @@ async def demo_oversubscribe():
         s = {"id": S["next_id"], "connector_id": None, "arrival": sim.now, "departure": sim.now + timedelta(hours=2),
              "user_stated_departure": sim.now + timedelta(hours=2), "kwh_needed": round(rnd.uniform(8, 10), 1),
              "kwh_delivered": 0.0, "boost": False, "status": "pending", "ended_at": None}
-        if sim.arrive(s):
-            added.append(s["id"])
-            await db.save_session(s)
+        sim.arrive(s)
+        added.append(s["id"])
+        await db.save_session(s)
     active = charging_sessions()
-    detail = {"added": len(added), "session_ids": added, "connectors_active": len(active),
+    detail = {"added": len(added), "session_ids": added, "connectors_active": len(active), "waiting": len(sim.waiting),
               "demand_kw_if_all_full_power": len(active) * S["site"]["p_max_kw"], "feed_kw": S["site"]["feed_kw"],
               "kwh_due_in_2h": round(sum(s["kwh_needed"] - s["kwh_delivered"] for s in active if s["user_stated_departure"] <= sim.now + timedelta(hours=2)), 1)}
     await event("demo", {"what": "oversubscribe", **detail})
diff --git a/noonshift/models.py b/noonshift/models.py
index 24c4761..69a7ecb 100644
--- a/noonshift/models.py
+++ b/noonshift/models.py
@@ -9,10 +9,23 @@
 
 
 # ---- REST ----
+class Vehicle(BaseModel):
+    """What the driver tells us about the car. All optional: the brain plans with the bay's limit when it knows nothing."""
+    model: str | None = None
+    battery_kwh: float | None = Field(None, gt=0)
+    max_kw: float | None = Field(None, gt=0)  # the car's own AC limit (3.7 / 7 / 11 kW are common)
+
+
+NeedConfidence = Literal["declared", "history", "site"]  # solutions.md §11: where kwh_needed came from
+
+
 class SessionIn(BaseModel):
     connector_id: str
     departure_at: datetime
     kwh_needed: float | None = None
+    vehicle: Vehicle | None = None
+    soc_now: float | None = Field(None, ge=0, le=1)  # with vehicle.battery_kwh: kwh_needed = (target - now) * battery
+    target_soc: float = Field(1.0, gt=0, le=1)
 
 
 Urgency = Literal["now", "soon", "priority"]  # business.md §4b: three bands, one price (R)
@@ -43,6 +56,9 @@ class SessionOut(BaseModel):
     price: Price
     boost: bool
     urgency: Urgency | None = None  # set by POST /sessions/{id}/urgency (or /boost = "now"); price is then exactly R
+    kwh_needed: float = 0.0
+    need_confidence: NeedConfidence | None = None
+    max_kw: float | None = None  # what the brain plans with: min(bay, car), corrected by the observation guard
 
 
 class LiveOut(BaseModel):
@@ -76,6 +92,8 @@ class StatusOut(BaseModel):
     block_kw: float = 0.0
     sim_time: datetime | None = None
     safe_share_kw: float = 0.0  # per-connector static share every charger reverts to when the controller is gone
+    waiting: int = 0  # cars that arrived with no free bay
+    connectors_asap: list[str] = []  # fleet bays that are never deferred
 
 
 class PriceTier(BaseModel):
@@ -148,6 +166,12 @@ class ConnectorMeter(BaseModel):
     departure_at: datetime | None  # what the driver told us
     boost: bool
     urgency: Urgency | None = None
+    idle_min: int = 0  # minutes since the car was full and still plugged in
+    need_confidence: NeedConfidence | None = None
+    p_max_kw: float = 0.0  # what the brain plans with for this car
+    cap_observed: bool = False  # the meter said the car draws less than we planned; p_max_kw was lowered to match
+    asap: bool = False  # a connectors_asap bay
+    move_by: bool = False  # deadline tightened to make room for a waiting car
 
 
 class MeterMsg(BaseModel):
@@ -158,12 +182,13 @@ class MeterMsg(BaseModel):
     building_load_kw: float
     feed_kw: float
     connectors: list[ConnectorMeter]
+    waiting: int = 0
 
 
 class EventMsg(BaseModel):
     type: Literal["event"] = "event"
     sim_time: datetime
-    name: Literal["plug_in", "unplug", "deadline", "boost", "urgency", "dr", "demo", "mode", "day_reset"]
+    name: Literal["plug_in", "unplug", "deadline", "boost", "urgency", "done", "cap_observed", "move_by", "dr", "demo", "mode", "day_reset"]
     detail: dict
 
 
diff --git a/noonshift/sim.py b/noonshift/sim.py
index b46779f..8804c94 100644
--- a/noonshift/sim.py
+++ b/noonshift/sim.py
@@ -10,6 +10,7 @@
 SLOT = timedelta(minutes=5)
 START_HOUR = 6  # nothing happens before 06:00; skip it
 DYN_VALID_MIN = 15  # a dynamic limit expires this many minutes after it was last set (OCPP profile valid_to); then safe share
+MOVE_AFTER_MIN = 10  # Assumption A5: a driver told "done, please move" vacates within this when someone is waiting
 
 
 def safe_share_kw(site):
@@ -43,6 +44,7 @@ def __init__(self, id, p_max_kw=7.0, safe_kw=None):
         self.session = None
         self.limit_kw = self.safe_kw
         self.dyn_left = 0
+        self.slow_min = 0  # api.observe_caps: consecutive minutes drawing well under the limit
         self.kw = 0.0
 
     @property
@@ -70,7 +72,8 @@ def tick(self, minutes):
             return
         frac = s["kwh_delivered"] / s["kwh_needed"]
         taper = 1.0 if frac < 0.8 else max(0.1, (1 - frac) / 0.2)  # battery taper: linear from 80% to ~10% at full
-        self.kw = min(self.limit_kw, self.p_max_kw * taper)
+        car_kw = min(self.p_max_kw, s.get("car_kw") or self.p_max_kw)  # the car's own onboard charger limit
+        self.kw = min(self.limit_kw, car_kw * taper)
         s["kwh_delivered"] = min(s["kwh_needed"], s["kwh_delivered"] + self.kw * minutes / 60)
         if s["kwh_delivered"] >= s["kwh_needed"] - 1e-6:
             s["status"], self.kw = "done", 0.0
@@ -87,6 +90,7 @@ def __init__(self, sessions, site, connector_cls=Connector):
         self.now = day + timedelta(hours=START_HOUR)
         self.day_end = day + timedelta(days=1)
         self.pending = sorted(sessions, key=lambda s: s["arrival"])
+        self.waiting = []  # arrived, no free bay (solutions.md §3); plugged in as bays free up, first come first served
         self.connectors = {cid: connector_cls(cid, site["p_max_kw"], safe_share_kw(site)) for cid in site["connectors"]}
         self.sessions = {s["id"]: s for s in sessions}
 
@@ -97,28 +101,39 @@ def free_connector(self, preferred=None):
         return next((c for c in self.connectors.values() if not c.session), None)
 
     def arrive(self, session):
-        """Plug a session in now. Returns the connector, or None if the lot is full."""
+        """Plug a session in now. Returns the connector, or None if the lot is full (the car then waits)."""
+        self.sessions[session["id"]] = session
         c = self.free_connector(session.get("connector_id"))
         if c:
-            self.sessions[session["id"]] = session
             c.plug_in(session)
+        elif session not in self.waiting:
+            self.waiting.append(session)
         return c
 
     def tick(self, minutes=1):
-        """Advance the clock. Returns [{"name": "plug_in"|"unplug", "session_id", "connector_id"}]."""
+        """Advance the clock. Returns [{"name": "plug_in"|"unplug"|"done", "session_id", "connector_id"}]."""
         for c in self.connectors.values():
             c.tick(minutes)
         self.now += timedelta(minutes=minutes)
         events = []
         for c in self.connectors.values():
-            if c.session and c.session["departure"] <= self.now:
+            s = c.session
+            if s and s["status"] == "done" and not s.get("idle_since"):
+                s["idle_since"] = self.now
+                events.append({"name": "done", "session_id": s["id"], "connector_id": c.id})
+            moved = s and s.get("idle_since") and self.waiting and self.now - s["idle_since"] >= timedelta(minutes=MOVE_AFTER_MIN)
+            if s and (s["departure"] <= self.now or moved):
                 s = c.unplug(self.now)
-                events.append({"name": "unplug", "session_id": s["id"], "connector_id": c.id})
+                events.append({"name": "unplug", "session_id": s["id"], "connector_id": c.id, "moved": bool(moved)})
         while self.pending and self.pending[0]["arrival"] <= self.now:
             s = self.pending.pop(0)
             c = self.arrive(s)
             if c:
                 events.append({"name": "plug_in", "session_id": s["id"], "connector_id": c.id})
+        while self.waiting and self.free_connector():
+            s = self.waiting.pop(0)
+            c = self.arrive(s)
+            events.append({"name": "plug_in", "session_id": s["id"], "connector_id": c.id, "waited_min": int((self.now - s["arrival"]).total_seconds() // 60)})
         return events
 
     def active(self):
diff --git a/scripts/smoke.py b/scripts/smoke.py
index bb78f95..1a1d39d 100644
--- a/scripts/smoke.py
+++ b/scripts/smoke.py
@@ -41,7 +41,7 @@ async def pump():
         assert meters, "no meter frames on /ws"
         sim_now = datetime.fromisoformat(meters[-1]["sim_time"])
         st = http("GET", "/sites/site-1/status")
-        assert st["feed_kw"] > 0 and st["block_kw"] > 0 and st["sim_time"], st
+        assert st["feed_kw"] > 0 and st["block_kw"] > 0 and st["sim_time"] and st["safe_share_kw"] > 0 and st["connectors_asap"], st
         free = [c["connector_id"] for c in meters[-1]["connectors"] if c["session_id"] is None]
         connector = free[-1]
         print(f"[ws]     sim_time={sim_now}  mode={st['mode']}  feed={st['feed_kw']} kW block={st['block_kw']} kW  free={len(free)} -> driver takes {connector}")
@@ -85,6 +85,17 @@ async def pump():
                   for cid in (free[-2], free[-3])]
         await asyncio.sleep(1.5)
 
+        # 5b. a fleet van on a connectors_asap bay is never deferred; a PHEV form caps the plan at the car's 3.3 kW
+        van = http("POST", "/sessions", {"connector_id": st["connectors_asap"][0], "departure_at": departure, "kwh_needed": 20})
+        phev = http("POST", "/sessions", {"connector_id": free[-4], "departure_at": departure,
+                                          "vehicle": {"model": "PHEV", "battery_kwh": 40, "max_kw": 3.3}, "soc_now": 0.7, "target_soc": 0.9})
+        assert van["plan"]["start"] and phev["kwh_needed"] == 8.0 and phev["need_confidence"] == "declared" and phev["max_kw"] == 3.3
+        await asyncio.sleep(1.5)
+        plans = frames_of(frames, "plan")[-1]["connectors"]
+        assert max(next(c["kw"] for c in plans if c["session_id"] == phev["session_id"])) <= 3.3
+        assert next(c["kw"] for c in plans if c["session_id"] == van["session_id"])[0] == 7.0, "asap bay: full power now"
+        print(f"[driver] van on {st['connectors_asap'][0]} at full power; PHEV form -> {phev['kwh_needed']} kWh ({phev['need_confidence']}) capped at {phev['max_kw']} kW")
+
         # 6a. the emergency bands (business.md §4b): "soon" moves the deadline, "priority" keeps it; both pay exactly R
         soon_at = (sim_now + timedelta(hours=1, minutes=30)).replace(second=0, microsecond=0).isoformat()
         u1 = http("POST", f"/sessions/{others[0]}/urgency", {"level": "soon", "leave_at": soon_at})
@@ -100,7 +111,7 @@ async def pump():
         for path, body in (("/demo/early_unplug", None), ("/demo/boost", None), ("/demo/oversubscribe", None),
                            ("/demo/signal_outage", {"rungs": ["live"]})):
             d = http("POST", path, body)
-            print(f"[ops]    POST {path} -> {d['changed']}")
+            print(f"[ops]    POST {path} -> {d['changed']}" + (f" (waiting {d['detail']['waiting']})" if "waiting" in d["detail"] else ""))
         await asyncio.sleep(2.5)
         assert frames_of(frames, "event", name="unplug"), "unplug event not broadcast"
         assert frames_of(frames, "event", name="mode"), "mode event not broadcast"
diff --git a/tests/data/site.json b/tests/data/site.json
index c020fa9..07429ec 100644
--- a/tests/data/site.json
+++ b/tests/data/site.json
@@ -1 +1 @@
-{"id": "site-1", "feed_kw": 150, "block_kw": 100, "connectors": ["c01", "c02", "c03", "c04", "c05", "c06", "c07", "c08", "c09", "c10", "c11", "c12", "c13", "c14", "c15", "c16", "c17", "c18", "c19", "c20", "c21", "c22", "c23", "c24", "c25", "c26", "c27", "c28", "c29", "c30", "c31", "c32", "c33", "c34", "c35", "c36", "c37", "c38", "c39", "c40", "c41", "c42", "c43", "c44", "c45", "c46", "c47", "c48", "c49", "c50", "c51", "c52", "c53", "c54", "c55", "c56", "c57", "c58", "c59", "c60"], "p_max_kw": 7.0, "building_load_kw": [20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 21.7, 23.3, 25.0, 26.7, 28.3, 30.0, 31.7, 33.3, 35.0, 36.7, 38.3, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 38.3, 36.7, 35.0, 33.3, 31.7, 30.0, 28.3, 26.7, 25.0, 23.3, 21.7, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0], "employee_rate_usd_per_kwh": 0.25, "driver_share": 0.5, "noonshift_share": 0.2, "safe_share_kw": 1.833}
\ No newline at end of file
+{"id": "site-1", "feed_kw": 150, "block_kw": 100, "connectors": ["c01", "c02", "c03", "c04", "c05", "c06", "c07", "c08", "c09", "c10", "c11", "c12", "c13", "c14", "c15", "c16", "c17", "c18", "c19", "c20", "c21", "c22", "c23", "c24", "c25", "c26", "c27", "c28", "c29", "c30", "c31", "c32", "c33", "c34", "c35", "c36", "c37", "c38", "c39", "c40", "c41", "c42", "c43", "c44", "c45", "c46", "c47", "c48", "c49", "c50", "c51", "c52", "c53", "c54", "c55", "c56", "c57", "c58", "c59", "c60"], "p_max_kw": 7.0, "building_load_kw": [20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 21.7, 23.3, 25.0, 26.7, 28.3, 30.0, 31.7, 33.3, 35.0, 36.7, 38.3, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 40.0, 38.3, 36.7, 35.0, 33.3, 31.7, 30.0, 28.3, 26.7, 25.0, 23.3, 21.7, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0, 20.0], "employee_rate_usd_per_kwh": 0.25, "driver_share": 0.5, "noonshift_share": 0.2, "safe_share_kw": 1.833, "connectors_asap": ["c41", "c42"]}
\ No newline at end of file
diff --git a/tests/test_day.py b/tests/test_day.py
index 9ca3918..af21d43 100644
--- a/tests/test_day.py
+++ b/tests/test_day.py
@@ -246,3 +246,92 @@ def test_when_the_control_loop_dies_the_site_falls_back_to_the_static_share(mid_
     assert worst_headroom <= 1e-6, f"site exceeded its headroom by {worst_headroom:.1f} kW with the loop dead"
     assert worst_after <= 1e-6, f"after {DYN_VALID_MIN} min the site drew {worst_after:.1f} kW above n * safe share"
     assert all(c.limit_kw == share for c in sim.active()), "every plugged car sits on the static share"
+
+
+# ---- WP3: cars, needs, queues (solutions.md §3, §10, §11) ----
+class Sink:
+    """A fake /ws client: collects every broadcast frame."""
+    def __init__(self):
+        self.msgs = []
+
+    async def send_json(self, m):
+        self.msgs.append(m)
+
+    def events(self, name):
+        return [m["detail"] for m in self.msgs if m.get("type") == "event" and m["name"] == name]
+
+
+def plug(connector_id, hours=4, **body):
+    from noonshift.api import create_session
+    from noonshift.models import SessionIn
+    return asyncio.run(create_session(SessionIn(connector_id=connector_id, departure_at=S["sim"].now + timedelta(hours=hours), **body)))
+
+
+def test_a_3_3_kw_car_on_a_7_kw_bay_is_planned_at_3_3_and_meets_its_deadline(mid_morning):
+    from noonshift.api import car
+    out = plug("c50", hours=4, vehicle={"model": "PHEV", "battery_kwh": 40, "max_kw": 3.3}, soc_now=0.7, target_soc=0.9)
+    s = mid_morning.sessions[out.session_id]
+    assert out.kwh_needed == pytest.approx(8.0) and out.need_confidence == "declared" and out.max_kw == 3.3
+    assert car(mid_morning.connectors["c50"])["p_max_kw"] == 3.3
+    assert max(S["plan"]["c50"]) <= 3.3 + 1e-9, "the brain never plans more than the car can take"
+    asyncio.run(play_until(s["user_stated_departure"]))
+    assert s["kwh_delivered"] == pytest.approx(8.0, abs=0.1), "8 kWh at 3.3 kW fits in 4 h and lands"
+
+
+def test_need_comes_from_history_or_the_site_when_the_driver_types_nothing(mid_morning):
+    out = plug("c51", hours=5)
+    assert out.need_confidence in ("history", "site") and out.kwh_needed > 0
+    assert out.kwh_needed == pytest.approx(8.0, abs=2.0), "the frozen day's median need, not a magic number"
+
+
+def test_observation_guard_believes_the_meter_over_the_plan(mid_morning):
+    """A car the form calls a 7 kW car draws 3.3 kW (PHEV, cold battery). After 5 minutes under 80 % of its limit the
+    brain caps it at metered * 1.05 and says so; from then on the plan never asks for more than the car can take."""
+    from noonshift.api import car
+    sink = Sink()
+    S["clients"].add(sink)
+    out = plug("c52", hours=6, kwh_needed=9.0)
+    s = mid_morning.sessions[out.session_id]
+    s["car_kw"] = 3.3  # the physical truth the sim knows and the brain does not
+    asyncio.run(urgency(out.session_id, UrgencyIn(level="now")))  # full power asked, so the gap shows
+    asyncio.run(play_until(mid_morning.now + timedelta(minutes=7)))
+    assert s["cap_observed"] and s["max_kw"] == pytest.approx(3.3 * 1.05, abs=0.02)
+    caps = sink.events("cap_observed")
+    assert caps and caps[-1]["connector_id"] == "c52" and caps[-1]["limit_kw"] > caps[-1]["metered_kw"]
+    assert car(mid_morning.connectors["c52"])["p_max_kw"] == pytest.approx(3.47, abs=0.02)
+    assert max(S["plan"]["c52"]) <= 3.47 + 1e-6
+    S["clients"].discard(sink)
+
+
+def test_asap_bay_is_never_deferred(mid_morning):
+    from noonshift.api import car
+    out = plug("c41", hours=8, kwh_needed=20.0)  # site.json connectors_asap: a loading-dock bay, 8 h of slack
+    assert car(mid_morning.connectors["c41"])["boost"] is True
+    assert S["plan"]["c41"][:6] == [S["site"]["p_max_kw"]] * 6, "full power from the first slot despite 8 h of slack"
+    assert out.boost is False, "the session itself is not a driver Boost; the bay is configured that way"
+
+
+def test_a_queue_tightens_the_slackest_car_and_a_bay_frees(mid_morning):
+    from noonshift.api import site_status
+    sink = Sink()
+    S["clients"].add(sink)
+    for _ in range(3):  # 36 replayed + 60 late cars > 60 bays
+        asyncio.run(demo_oversubscribe())
+    sim = mid_morning
+    waiting = [s["id"] for s in sim.waiting]
+    assert waiting and site_status("site-1").waiting == len(waiting)
+    moved = [c.session for c in sim.active() if c.session.get("move_by")]
+    assert moved, "at least one plugged car got a move-by time"
+    for s in moved:
+        finish = sim.now + timedelta(hours=(s["kwh_needed"] - s["kwh_delivered"]) / S["site"]["p_max_kw"])
+        assert finish <= s["user_stated_departure"] <= finish + timedelta(minutes=6), "deadline = now + time to finish at full power"
+        assert not s.get("urgent")
+    assert len(moved) <= len(waiting), "one tightened car per waiting car"
+    assert sink.events("move_by") and all(e["waiting"] > 0 for e in sink.events("move_by"))
+    asyncio.run(play_until(sim.now + timedelta(hours=4)))
+    plugged_later = [e for e in sink.events("plug_in") if e["session_id"] in waiting]
+    assert plugged_later and all(e["waited_min"] > 0 for e in plugged_later), "waiting cars got a bay as bays freed"
+    assert len(sim.waiting) < len(waiting)
+    dones = sink.events("done")
+    assert dones, "a full car raises a done event (the 'please move' notification)"
+    S["clients"].discard(sink)