diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 3f16b85..feaed9e 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -12,6 +12,18 @@ updates:
       interval: weekly
       day: monday
     open-pull-requests-limit: 5
+    ignore:
+      # `@types/vscode` tracks `engines.vscode`, not the latest release, and is
+      # pinned exactly (no caret) so the compiler enforces the floor instead of
+      # merely declaring it. `engines.vscode` is the OLDEST editor the extension
+      # supports; types newer than that let a call added in a later VS Code
+      # typecheck cleanly and then fail on the editor we promised to run on.
+      # `vsce package` refuses the mismatch outright:
+      #   ERROR  @types/vscode ^1.125.0 greater than engines.vscode ^1.85.0
+      # Taking such a bump means dropping every VS Code in between — a support
+      # decision, not a dependency update. Raise `engines.vscode` deliberately
+      # and move the types with it, together.
+      - dependency-name: '@types/vscode'
     groups:
       typescript:
         patterns:
diff --git a/apps/vscode/package.json b/apps/vscode/package.json
index c9555aa..5d3426a 100644
--- a/apps/vscode/package.json
+++ b/apps/vscode/package.json
@@ -124,7 +124,7 @@
   },
   "devDependencies": {
     "@types/node": "^22.10.0",
-    "@types/vscode": "^1.85.0",
+    "@types/vscode": "1.85.0",
     "@vscode/vsce": "^3.9.2",
     "esbuild": "^0.21.5",
     "typescript": "^5.7.0",
diff --git a/package.json b/package.json
index e8c005a..ce47c8d 100644
--- a/package.json
+++ b/package.json
@@ -36,7 +36,7 @@
     "husky": "^9.1.0",
     "prettier": "^3.9.6",
     "typescript": "^5.7.0",
-    "typescript-eslint": "^8.61.1",
+    "typescript-eslint": "^8.67.0",
     "vitest": "^4.1.10"
   }
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 9b75435..6cb11db 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -27,8 +27,8 @@ importers:
         specifier: ^5.7.0
         version: 5.9.3
       typescript-eslint:
-        specifier: ^8.61.1
-        version: 8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
+        specifier: ^8.67.0
+        version: 8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
       vitest:
         specifier: ^4.1.10
         version: 4.1.10(@types/node@22.19.19)(vite@8.2.1(@types/node@22.19.19)(esbuild@0.21.5)(jiti@1.21.7))
@@ -176,8 +176,8 @@ importers:
         specifier: ^22.10.0
         version: 22.19.19
       '@types/vscode':
-        specifier: ^1.85.0
-        version: 1.120.0
+        specifier: 1.85.0
+        version: 1.85.0
       '@vscode/vsce':
         specifier: ^3.9.2
         version: 3.9.2
@@ -792,66 +792,66 @@ packages:
   '@types/sarif@2.1.7':
     resolution: {integrity: sha512-kRz0VEkJqWLf1LLVN4pT1cg1Z9wAuvI6L97V3m2f5B76Tg8d413ddvLBPTEHAZJlnn4XSvu0FkZtViCQGVyrXQ==}
 
-  '@types/vscode@1.120.0':
-    resolution: {integrity: sha512-feaT4Rst+FkTch5zz/ZbNCxoIvo55YU80Be2kiL7OJcod4+CUYf2lUBPdIJzozNnSEMq1VRTGrWEcCGFB3fBmA==}
+  '@types/vscode@1.85.0':
+    resolution: {integrity: sha512-CF/RBon/GXwdfmnjZj0WTUMZN5H6YITOfBCP4iEZlOtVQXuzw6t7Le7+cR+7JzdMrnlm7Mfp49Oj2TuSXIWo3g==}
 
-  '@typescript-eslint/eslint-plugin@8.65.0':
-    resolution: {integrity: sha512-IEgob78X12rHpUmtcwFsXhZdVGJtwTVP8FiCLZkR6GlYVrl2PcuB+KhCE5BlVC/eQpQnu8WXRtkHZuPar+gCRA==}
+  '@typescript-eslint/eslint-plugin@8.67.0':
+    resolution: {integrity: sha512-Un7Heoyj65NREbKAyIrFxeM143NZpExWmy1Nep4DLeQOeLlTeumPjoNKnBrU5D5moWXbPJgRa5Uwcdu0faVNGQ==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
-      '@typescript-eslint/parser': ^8.65.0
+      '@typescript-eslint/parser': ^8.67.0
       eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
       typescript: '>=4.8.4 <6.1.0'
 
-  '@typescript-eslint/parser@8.65.0':
-    resolution: {integrity: sha512-CZ4nMxWwgu1HEEFNkeaCptra9QCtkmKdgf3sWh1rl1trIhmxLilgTV4cwcbQ4wemnT4sWQN8CaKOmdYx+g2gMA==}
+  '@typescript-eslint/parser@8.67.0':
+    resolution: {integrity: sha512-fUBfTuuEulWqX6V8+O3PtScV01tzYYRUDTAirHFKoRAt7nOzoGiPt0M/bB47wWNy0coOOcgEwAMUtBpykMxl6w==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
       typescript: '>=4.8.4 <6.1.0'
 
-  '@typescript-eslint/project-service@8.65.0':
-    resolution: {integrity: sha512-SxnPhbTsGahizDgbu7oqFH/xVtzIqMd/s+WtnSxNxJZJpLbdT5IPdzg8EZxO3+PoKahXmwJLeNQOpKJb3/bi7Q==}
+  '@typescript-eslint/project-service@8.67.0':
+    resolution: {integrity: sha512-cvE8c7ulYeXN9fYuszhCeCsbzyVEXuhrRCybnBre7TUmqb5nRmBfQAwCj0O3WJFDeyAZt4VYv51vMCC9LHSdYw==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       typescript: '>=4.8.4 <6.1.0'
 
-  '@typescript-eslint/scope-manager@8.65.0':
-    resolution: {integrity: sha512-Esbl8OSYiVxBokYgWPf7VVWg/BE798wXhimnn9ML9Pt5qoDf8bfQlgjlKXR/k98+AcNzlLKYrpCcrcuZ9DZLgg==}
+  '@typescript-eslint/scope-manager@8.67.0':
+    resolution: {integrity: sha512-EgvsleTwS4E+WzzSvem8fAUubLwatMNF1B5hHSLQxcvs7q2dtRhGyujHwLJSYlG41niJ7GP24Aha2+0mb1b2kg==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  '@typescript-eslint/tsconfig-utils@8.65.0':
-    resolution: {integrity: sha512-j6GzGqCiRdA7Qhur2VVmKZAkBLfnHFQfx4TaJGL9RMveZqCo48jSHHO0DTgizEnGhtWnqmbtCUSrqSkdiY/0Hg==}
+  '@typescript-eslint/tsconfig-utils@8.67.0':
+    resolution: {integrity: sha512-vV+LUSv5njUWsknE71fqKTlXUva+R76SaeORd6Zojcunk/6DvKFXONU3BrAs2H49mbygUXt6gbYunzwqNwlhdg==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       typescript: '>=4.8.4 <6.1.0'
 
-  '@typescript-eslint/type-utils@8.65.0':
-    resolution: {integrity: sha512-YjaZ7PRI5qY7ax2L3PbvX0rRyGtipAReCWs0mhhDBHjH/vl0g0BonaGXrKdKpMbIIsMIwDgbk/xzkBTyAltS5g==}
+  '@typescript-eslint/type-utils@8.67.0':
+    resolution: {integrity: sha512-aVWDXbRmdXO9siTfX4ditQI1T9+zVcNazT48EJCD0v40/9RIFoUgZ05CmGEq9H2gixRpjUn/iplwvlcvutJW/Q==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
       typescript: '>=4.8.4 <6.1.0'
 
-  '@typescript-eslint/types@8.65.0':
-    resolution: {integrity: sha512-JSSwWNy+H0E/01jJEM+hrX6N0OFDzFzeIhHFSAS01tlVaevpG8cFyYRPhS5yjGOvBUx3sqQHVMjCL1CAZZMxBg==}
+  '@typescript-eslint/types@8.67.0':
+    resolution: {integrity: sha512-sBtgslww8nsMYUjhdPBiSyUqSzT8uR6g93A2QXnQC8+cGdjz0CyaOdqHDRJb1AtORbZCNUJBBeFA/tNR2uQmww==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  '@typescript-eslint/typescript-estree@8.65.0':
-    resolution: {integrity: sha512-JboAE2swaYt4tb1fHhHTABE2K+OLy09XfcTbhnk4Pw96f9dd2e9iYsJ28gBggHlo5z5x1rkyWvcPoTuNTd4oGg==}
+  '@typescript-eslint/typescript-estree@8.67.0':
+    resolution: {integrity: sha512-EKQBCE9yNlRJYm7jdTW5AhDacDUmSwQb0FAJAmK2EKYrNXIsa2vxcSZx6PvJ/dEdI6lS+Y9W+EXckLj0iPFGcw==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       typescript: '>=4.8.4 <6.1.0'
 
-  '@typescript-eslint/utils@8.65.0':
-    resolution: {integrity: sha512-gXiwIHsYreboxeJucHKPvgwl7dXt50mF8s1/c00cP/WoVTyWKFdtfhRWwZiXYFU5H2O8vVoSLNrexFZjYS/SGA==}
+  '@typescript-eslint/utils@8.67.0':
+    resolution: {integrity: sha512-U9D1FdwEWBwok3hxxSdhclMb0twvt9QnjIQ0VfQ1AiX2epnpSgv2ubVDsayOFyY8K6FX+AQ7E0FKWVG3iKsj1A==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
       typescript: '>=4.8.4 <6.1.0'
 
-  '@typescript-eslint/visitor-keys@8.65.0':
-    resolution: {integrity: sha512-8C71BQkGjiMmXtop7pHVJu1l2NNShFdkCyD6a2ezzs5vU/L3LRtb69EtcteFwz0mYMPzIgOw0n6OV4VBUWZd7A==}
+  '@typescript-eslint/visitor-keys@8.67.0':
+    resolution: {integrity: sha512-fkv8dHRDqfGtTHuJeebdrQ7cX6Ad4WAS00rgHh9UGvMycF1mjBfsxry1XsLIFhWZ6Judlh6UdzK+TYlbpCXgnA==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
   '@typespec/ts-http-runtime@0.3.8':
@@ -2173,6 +2173,11 @@ packages:
     engines: {node: '>=10'}
     hasBin: true
 
+  semver@7.8.5:
+    resolution: {integrity: sha512-Y7/KDsb8LjooZpwaqGyulO6DQlksgCncchHGk+sZIY4SBvUocMBEFH5Ur1fI4dV+Jvl0w6cjvucaIi40puRioA==}
+    engines: {node: '>=10'}
+    hasBin: true
+
   send@1.2.1:
     resolution: {integrity: sha512-1gnZf7DFcoIcajTjTwjwuDjzuz4PPcY2StKPlsGAQ1+YH20IRVrBaXSWmdjowTJ6u8Rc01PoYOGHXfP1mYcZNQ==}
     engines: {node: '>= 18'}
@@ -2365,8 +2370,8 @@ packages:
   typed-rest-client@1.8.11:
     resolution: {integrity: sha512-5UvfMpd1oelmUPRbbaVnq+rHP7ng2cE4qoQkQeAqxRL6PklkxsM0g32/HL0yfvruK6ojQ5x8EE+HF4YV6DtuCA==}
 
-  typescript-eslint@8.65.0:
-    resolution: {integrity: sha512-/ggrHAwyjENDusvyxbuqxAC2dTnZg/Z8F+fgQtYIz+L6n/9HfSlEZcFGV/NsMNa6CkGk0xUjUAFwC0vHOflvIA==}
+  typescript-eslint@8.67.0:
+    resolution: {integrity: sha512-S2udFs8tCKEKffuJ4TB1idGUZiXdCPGi3IPBGWXarbLQ5UPXORV8QEVzJ4gCRduURMb5EkpNCdjbk0eDIuI8Yg==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
@@ -3079,16 +3084,16 @@ snapshots:
 
   '@types/sarif@2.1.7': {}
 
-  '@types/vscode@1.120.0': {}
+  '@types/vscode@1.85.0': {}
 
-  '@typescript-eslint/eslint-plugin@8.65.0(@typescript-eslint/parser@8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3))(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)':
+  '@typescript-eslint/eslint-plugin@8.67.0(@typescript-eslint/parser@8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3))(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)':
     dependencies:
       '@eslint-community/regexpp': 4.12.2
-      '@typescript-eslint/parser': 8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
-      '@typescript-eslint/scope-manager': 8.65.0
-      '@typescript-eslint/type-utils': 8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
-      '@typescript-eslint/utils': 8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
-      '@typescript-eslint/visitor-keys': 8.65.0
+      '@typescript-eslint/parser': 8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
+      '@typescript-eslint/scope-manager': 8.67.0
+      '@typescript-eslint/type-utils': 8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
+      '@typescript-eslint/utils': 8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
+      '@typescript-eslint/visitor-keys': 8.67.0
       eslint: 10.8.0(jiti@1.21.7)
       ignore: 7.0.6
       natural-compare: 1.4.0
@@ -3097,41 +3102,41 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/parser@8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)':
+  '@typescript-eslint/parser@8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)':
     dependencies:
-      '@typescript-eslint/scope-manager': 8.65.0
-      '@typescript-eslint/types': 8.65.0
-      '@typescript-eslint/typescript-estree': 8.65.0(typescript@5.9.3)
-      '@typescript-eslint/visitor-keys': 8.65.0
+      '@typescript-eslint/scope-manager': 8.67.0
+      '@typescript-eslint/types': 8.67.0
+      '@typescript-eslint/typescript-estree': 8.67.0(typescript@5.9.3)
+      '@typescript-eslint/visitor-keys': 8.67.0
       debug: 4.4.3
       eslint: 10.8.0(jiti@1.21.7)
       typescript: 5.9.3
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/project-service@8.65.0(typescript@5.9.3)':
+  '@typescript-eslint/project-service@8.67.0(typescript@5.9.3)':
     dependencies:
-      '@typescript-eslint/tsconfig-utils': 8.65.0(typescript@5.9.3)
-      '@typescript-eslint/types': 8.65.0
+      '@typescript-eslint/tsconfig-utils': 8.67.0(typescript@5.9.3)
+      '@typescript-eslint/types': 8.67.0
       debug: 4.4.3
       typescript: 5.9.3
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/scope-manager@8.65.0':
+  '@typescript-eslint/scope-manager@8.67.0':
     dependencies:
-      '@typescript-eslint/types': 8.65.0
-      '@typescript-eslint/visitor-keys': 8.65.0
+      '@typescript-eslint/types': 8.67.0
+      '@typescript-eslint/visitor-keys': 8.67.0
 
-  '@typescript-eslint/tsconfig-utils@8.65.0(typescript@5.9.3)':
+  '@typescript-eslint/tsconfig-utils@8.67.0(typescript@5.9.3)':
     dependencies:
       typescript: 5.9.3
 
-  '@typescript-eslint/type-utils@8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)':
+  '@typescript-eslint/type-utils@8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)':
     dependencies:
-      '@typescript-eslint/types': 8.65.0
-      '@typescript-eslint/typescript-estree': 8.65.0(typescript@5.9.3)
-      '@typescript-eslint/utils': 8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
+      '@typescript-eslint/types': 8.67.0
+      '@typescript-eslint/typescript-estree': 8.67.0(typescript@5.9.3)
+      '@typescript-eslint/utils': 8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
       debug: 4.4.3
       eslint: 10.8.0(jiti@1.21.7)
       ts-api-utils: 2.5.0(typescript@5.9.3)
@@ -3139,37 +3144,37 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/types@8.65.0': {}
+  '@typescript-eslint/types@8.67.0': {}
 
-  '@typescript-eslint/typescript-estree@8.65.0(typescript@5.9.3)':
+  '@typescript-eslint/typescript-estree@8.67.0(typescript@5.9.3)':
     dependencies:
-      '@typescript-eslint/project-service': 8.65.0(typescript@5.9.3)
-      '@typescript-eslint/tsconfig-utils': 8.65.0(typescript@5.9.3)
-      '@typescript-eslint/types': 8.65.0
-      '@typescript-eslint/visitor-keys': 8.65.0
+      '@typescript-eslint/project-service': 8.67.0(typescript@5.9.3)
+      '@typescript-eslint/tsconfig-utils': 8.67.0(typescript@5.9.3)
+      '@typescript-eslint/types': 8.67.0
+      '@typescript-eslint/visitor-keys': 8.67.0
       debug: 4.4.3
       minimatch: 10.2.6
-      semver: 7.8.1
+      semver: 7.8.5
       tinyglobby: 0.2.17
       ts-api-utils: 2.5.0(typescript@5.9.3)
       typescript: 5.9.3
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/utils@8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)':
+  '@typescript-eslint/utils@8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)':
     dependencies:
       '@eslint-community/eslint-utils': 4.10.1(eslint@10.8.0(jiti@1.21.7))
-      '@typescript-eslint/scope-manager': 8.65.0
-      '@typescript-eslint/types': 8.65.0
-      '@typescript-eslint/typescript-estree': 8.65.0(typescript@5.9.3)
+      '@typescript-eslint/scope-manager': 8.67.0
+      '@typescript-eslint/types': 8.67.0
+      '@typescript-eslint/typescript-estree': 8.67.0(typescript@5.9.3)
       eslint: 10.8.0(jiti@1.21.7)
       typescript: 5.9.3
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/visitor-keys@8.65.0':
+  '@typescript-eslint/visitor-keys@8.67.0':
     dependencies:
-      '@typescript-eslint/types': 8.65.0
+      '@typescript-eslint/types': 8.67.0
       eslint-visitor-keys: 5.0.1
 
   '@typespec/ts-http-runtime@0.3.8':
@@ -4538,6 +4543,8 @@ snapshots:
 
   semver@7.8.1: {}
 
+  semver@7.8.5: {}
+
   send@1.2.1:
     dependencies:
       debug: 4.4.3
@@ -4770,12 +4777,12 @@ snapshots:
       tunnel: 0.0.6
       underscore: 1.13.8
 
-  typescript-eslint@8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3):
+  typescript-eslint@8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3):
     dependencies:
-      '@typescript-eslint/eslint-plugin': 8.65.0(@typescript-eslint/parser@8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3))(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
-      '@typescript-eslint/parser': 8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
-      '@typescript-eslint/typescript-estree': 8.65.0(typescript@5.9.3)
-      '@typescript-eslint/utils': 8.65.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
+      '@typescript-eslint/eslint-plugin': 8.67.0(@typescript-eslint/parser@8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3))(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
+      '@typescript-eslint/parser': 8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
+      '@typescript-eslint/typescript-estree': 8.67.0(typescript@5.9.3)
+      '@typescript-eslint/utils': 8.67.0(eslint@10.8.0(jiti@1.21.7))(typescript@5.9.3)
       eslint: 10.8.0(jiti@1.21.7)
       typescript: 5.9.3
     transitivePeerDependencies:
diff --git a/scripts/vscode-types-engine.test.ts b/scripts/vscode-types-engine.test.ts
new file mode 100644
index 0000000..eb3435b
--- /dev/null
+++ b/scripts/vscode-types-engine.test.ts
@@ -0,0 +1,62 @@
+// `@types/vscode` may never be newer than `engines.vscode`.
+//
+// `engines.vscode` states the OLDEST VS Code the extension supports. The types
+// have to match that floor, not the newest release: compiling against 1.125's
+// API surface while claiming to run on 1.85 lets an editor-version-gated call
+// typecheck cleanly and then throw `undefined is not a function` on the older
+// editor nobody tested.
+//
+// `vsce package` already enforces this and refuses to build:
+//
+//   ERROR  @types/vscode ^1.125.0 greater than engines.vscode ^1.85.0
+//
+// but only inside `pnpm release:check`, several minutes into CI and after a
+// full workspace build. A dependency bot proposing the newer types (#262) is
+// the ordinary way this happens, so catch it in the unit suite where the
+// message arrives in seconds — and where it names the reason rather than the
+// symptom.
+//
+// Fixing it is not "take the bump": raising `engines.vscode` drops every VS
+// Code between the two versions, which is a support decision to make on
+// purpose. Move both together when you make it.
+
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import { describe, expect, it } from 'vitest';
+
+const root = resolve(import.meta.dirname, '..');
+const pkg = JSON.parse(readFileSync(resolve(root, 'apps/vscode/package.json'), 'utf8')) as {
+  engines: { vscode: string };
+  devDependencies: Record<string, string>;
+};
+
+/** `^1.85.0` → `[1, 85, 0]`. Ranges here are always a caret over an exact version. */
+function floor(range: string): number[] {
+  const match = /(\d+)\.(\d+)\.(\d+)/.exec(range);
+  if (!match) throw new Error(`cannot read a version out of ${JSON.stringify(range)}`);
+  return [Number(match[1]), Number(match[2]), Number(match[3])];
+}
+
+function compare(a: number[], b: number[]): number {
+  for (let i = 0; i < 3; i++) {
+    const diff = (a[i] ?? 0) - (b[i] ?? 0);
+    if (diff !== 0) return diff;
+  }
+  return 0;
+}
+
+describe('the VS Code extension', () => {
+  it('does not compile against a newer API than it claims to run on', () => {
+    const engine = pkg.engines.vscode;
+    const types = pkg.devDependencies['@types/vscode'];
+    expect(types, 'apps/vscode must declare @types/vscode').toBeTypeOf('string');
+
+    expect(
+      compare(floor(types!), floor(engine)),
+      `@types/vscode ${types} is newer than engines.vscode ${engine}. ` +
+        `The types must match the oldest supported editor, so either pin them back ` +
+        `or raise engines.vscode deliberately — raising it drops support for every ` +
+        `VS Code in between.`,
+    ).toBeLessThanOrEqual(0);
+  });
+});