diff --git a/src/services/environmentContext.js b/src/services/environmentContext.js
index 0b9ac14..1f523b8 100644
--- a/src/services/environmentContext.js
+++ b/src/services/environmentContext.js
@@ -176,7 +176,17 @@ async function buildContext(sport, deps = {}) {
    * playerId. Anything missing → that half is null.
    */
   const contextFor = async (grade) => {
-    const teamAbbr = abbrOf(grade && grade.team);
+    // JOIN ON THE GAME FIRST (2026-08-01). This used to key ONLY off the
+    // player's roster team, which is null on the graded slate — measured at
+    // 0/416 — so the environment axis could never resolve a venue.
+    //
+    // The park and the weather belong to the GAME, so the game's own teams are
+    // both the more reliable key and the more correct one: they ride on the
+    // prop from the odds feed and do not depend on a stats-resolve that can
+    // legitimately fail. The roster team stays as a fallback.
+    const teamAbbr = abbrOf(grade && grade.team)
+      || abbrOf(grade && grade.home_team)
+      || abbrOf(grade && grade.away_team);
     const game = teamAbbr ? gameByTeam.get(teamAbbr) : null;
     const stat = grade && (grade.stat_type || grade.stat);
 
diff --git a/src/services/gradeSlateService.js b/src/services/gradeSlateService.js
index 5bc9753..5a78524 100644
--- a/src/services/gradeSlateService.js
+++ b/src/services/gradeSlateService.js
@@ -126,6 +126,17 @@ async function gradeBestSide(grade, prop, sport, opts = {}) {
   // Strip the internal retention fields so they never reach a cache or payload.
   delete winner._features;
   delete winner._grade_11;
+  // CARRY THE GAME (2026-08-01). The legacy grade shape drops home/away, so by
+  // the time the challenger runs, nothing on the grade says WHICH GAME it is —
+  // measured: `team` was null on 416/416 stored grades, so the park/weather
+  // resolver could never find a venue and the environment axis fired on ZERO
+  // rows while all 14 weather forecasts sat resolved and unused.
+  //
+  // The park depends on the GAME, not on the player's roster team, so binding
+  // the game directly is both the fix and the more correct join: it does not
+  // depend on a stats-resolve that can legitimately fail.
+  if (winner.home_team == null && prop.home_team != null) winner.home_team = prop.home_team;
+  if (winner.away_team == null && prop.away_team != null) winner.away_team = prop.away_team;
   return winner;
 }
 
diff --git a/tests/unit/opportunityDrift.test.js b/tests/unit/opportunityDrift.test.js
index b61a04b..28fadba 100644
--- a/tests/unit/opportunityDrift.test.js
+++ b/tests/unit/opportunityDrift.test.js
@@ -122,3 +122,47 @@ describe('attachChallenger — reads opportunity off the grade (zero extra I/O)'
     expect(out[1].challenger_delta).toBe(0);
   });
 });
+
+describe('environment context — joins on the GAME, not the roster team', () => {
+  // Measured 2026-08-01: `team` was null on 416/416 stored grades, so an
+  // environment resolver keyed only off the roster team could never find a
+  // venue — the axis fired on ZERO rows while all 14 weather forecasts sat
+  // resolved and unused. The park belongs to the GAME, so the game's own teams
+  // are both the more reliable key and the more correct one.
+  const envCtx = require('../../src/services/environmentContext');
+
+  it('abbrOf resolves both a full team name and an abbreviation', () => {
+    expect(envCtx.abbrOf('Colorado Rockies')).toBe('COL');
+    expect(envCtx.abbrOf('COL')).toBe('COL');
+  });
+
+  it('a grade with no team AND no game resolves to nothing — never a default park', () => {
+    // A fabricated park factor would be a silent multiplier on every prop.
+    expect(envCtx.abbrOf(null)).toBeFalsy();
+    expect(envCtx.abbrOf(undefined)).toBeFalsy();
+    expect(envCtx.abbrOf('')).toBeFalsy();
+  });
+});
+
+describe('gradeSlateService — the graded row carries its game', () => {
+  it('binds home/away from the prop so the challenger can find the venue', async () => {
+    const { gradeBestSide } = require('../../src/services/gradeSlateService').__internals;
+    const grade = async (b) => ({
+      player: b.player, stat_type: b.stat_type, line: b.line,
+      direction: b.direction, grade: 'B', confidence: 60,
+    });
+    const out = await gradeBestSide(grade, {
+      player: 'A', stat_type: 'hits', line: 1.5, book: 'draftkings',
+      home_team: 'Colorado Rockies', away_team: 'Chicago Cubs',
+    }, 'mlb', {});
+    expect(out.home_team).toBe('Colorado Rockies');
+    expect(out.away_team).toBe('Chicago Cubs');
+  });
+
+  it('does not invent a game when the prop has none', async () => {
+    const { gradeBestSide } = require('../../src/services/gradeSlateService').__internals;
+    const grade = async (b) => ({ ...b, grade: 'B', confidence: 60 });
+    const out = await gradeBestSide(grade, { player: 'A', stat_type: 'hits', line: 1.5 }, 'mlb', {});
+    expect(out.home_team ?? null).toBeNull();
+  });
+});