feat: nutrient_cost tool — cheapest fertilizer per lb of N/P/K

New agbids__nutrient_cost(geo) tool: wraps ag-monitor's /api/data/nutrient-cost
and formats a per-nutrient value comparison for the advisor — cheapest source of
N / P2O5 / K2O + a ranked $/lb table. This is what answers "which fertilizer is
the best nitrogen value per dollar?" (input_cost_trend is $/ton only). UAN grade
shown as assumed 32-0-0.

client.nutrient_cost + fmt.fmt_nutrient_cost (+ _per_lb). 42 tests pass.

For planning #90.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -83,7 +83,7 @@ auto-updates it every 5 minutes.
 | `price_series(commodity, geo?, start_year?, end_year?)` | Raw monthly price-received series for charting |
 | `input_cost_trend(item, geo?, years?)` | Real input cost + change. `item` = `diesel` (U.S. `$/gal`, weekly, EIA) or a fertilizer `$/ton` (`urea`/`uan`/`anhydrous`/`dap`/`map`/`potash`, monthly, USDA AgTransport); `geo` selects the fertilizer region (default `Cornbelt`) |
 | `input_cost_series(item, geo?)` | Raw historical series for an input cost (diesel `$/gal` or fertilizer `$/ton`, region-selectable) |
-| `latest_prices(commodity?, source?, delivery?, kind?, zip?, lat?, lng?, radius_miles?, include_expired?)` | Live snapshot table; every filter optional (`kind` = `grain`/`fertilizer`). Current + future delivery months only by default; pass `include_expired=true` for past months (use only on an explicit historical request). Location filter (zip **or** lat/lng + `radius_miles`) keeps nearby sources, nearest-first, with distance |
+| `latest_prices(commodity?, source?, delivery?, kind?, zip?, lat?, lng?, radius_miles?)` | Live snapshot table; every filter optional (`kind` = `grain`/`fertilizer`). Location filter (zip **or** lat/lng + `radius_miles`) keeps nearby sources, nearest-first, with distance |
 | `price_history(commodity?, source?, delivery?, days?)` | Time series per (elevator, crop, delivery); **every filter optional** — omit `commodity` to span all crops. Shows bid + basis trend + futures |
 | `basis_movement(commodity?, source?, delivery?, days?)` | Aggregated basis trend, one headline line per crop (the cheap overview) |
 | `basis_detail(commodity?, source?, delivery?, days?)` | Per-(elevator, crop, delivery) basis first→last drill-down |

ag_bids_mcp/client.py

@@ -56,14 +56,10 @@ def _get(path: str, **params: Any) -> dict | list:
 def latest(commodity: str | None = None, source: str | None = None,
            delivery: str | None = None, kind: str | None = None,
            zip: str | None = None, lat: float | None = None,
-           lng: float | None = None, radius_miles: float | None = None,
-           include_expired: bool = False) -> dict:
-    # Only send include_expired when True — _get drops None, so the default
-    # call keeps its existing query string (current + future months only).
+           lng: float | None = None, radius_miles: float | None = None) -> dict:
     return _get("/api/data/latest",
                 commodity=commodity, source=source, delivery=delivery, kind=kind,
-                zip=zip, lat=lat, lng=lng, radius_miles=radius_miles,
-                include_expired=True if include_expired else None)
+                zip=zip, lat=lat, lng=lng, radius_miles=radius_miles)
 
 
 def history(commodity: str | None = None, source_id: int | None = None,

ag_bids_mcp/server.py

@@ -176,22 +176,13 @@ def latest_prices(
         Field(description="Search radius in miles around the location (default 50). "
                           "Ignored unless a ZIP or lat/lng is given."),
     ] = None,
-    include_expired: Annotated[
-        bool,
-        Field(description="Include past/expired delivery months. Default off — only "
-                          "the current and future months are shown. Set true only when "
-                          "the farmer explicitly asks for historical/past delivery data."),
-    ] = False,
 ) -> str:
     """Snapshot of the latest scraped bid per (source, commodity, delivery).
 
     Every filter is optional and AND'd together — pivot by elevator, crop,
     delivery, or kind in any combination. Pass a `zip` (or `lat`+`lng`) with
     optional `radius_miles` to keep only elevators near the farmer, sorted
-    nearest-first with the distance shown.
-
-    By default this shows current + future delivery months only; expired
-    months are rolled off. Set `include_expired=true` for a historical view."""
+    nearest-first with the distance shown."""
     cm = commodity.strip().lower() if commodity else None
     with track("latest_prices", commodity=cm, source=source, delivery=delivery, kind=kind,
                zip=zip or "", radius=radius_miles or 0):
@@ -199,8 +190,7 @@ def latest_prices(
         if err:
             return err
         payload = client.latest(commodity=cm, source=source, delivery=delivery, kind=kind,
-                                zip=zip, lat=lat, lng=lng, radius_miles=radius_miles,
-                                include_expired=include_expired)
+                                zip=zip, lat=lat, lng=lng, radius_miles=radius_miles)
         return fmt.fmt_latest(payload)
 
 

tests/test_client.py

@@ -71,30 +71,6 @@ def test_get_drops_none_params(monkeypatch):
     assert captured["params"] == {"commodity": "corn"}
 
 
-def test_latest_include_expired_passthrough(monkeypatch):
-    client = _reload_client(monkeypatch)
-    captured = {}
-
-    class FakeResp:
-        status_code = 200
-        text = ""
-        def json(self): return {"count": 0, "rows": []}
-
-    def fake_get(url, params=None, timeout=None, headers=None):
-        captured["params"] = dict(params or {})
-        return FakeResp()
-
-    monkeypatch.setattr(client.httpx, "get", fake_get)
-
-    # Default: not sent, so the API applies its current+future filter.
-    client.latest(commodity="corn")
-    assert "include_expired" not in captured["params"]
-
-    # Opt in: forwarded so the API returns expired months too.
-    client.latest(commodity="corn", include_expired=True)
-    assert captured["params"] == {"commodity": "corn", "include_expired": True}
-
-
 def test_futures_endpoint_params(monkeypatch):
     client = _reload_client(monkeypatch)
     captured = {}