diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cc87b2fd120..10816a3bc68 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -593,7 +593,7 @@ jobs:
         working-directory: ${{ steps.tmp-dir.outputs.path }}
 
       - name: Test installation
-        run: npx rescript -h && npx rescript-legacy build && cat src/Test.res.js
+        run: npx rescript -h && npx rescript build && cat src/Test.res.js
         shell: bash
         working-directory: ${{ steps.tmp-dir.outputs.path }}
 
@@ -646,7 +646,7 @@ jobs:
         working-directory: ${{ steps.tmp-dir.outputs.path }}
 
       - name: Test installation
-        run: pnpm rescript -h && pnpm rescript-legacy build && cat src/Test.res.js
+        run: pnpm rescript -h && pnpm rescript build && cat src/Test.res.js
         shell: bash
         working-directory: ${{ steps.tmp-dir.outputs.path }}
 
diff --git a/packages/playground/package.json b/packages/playground/package.json
index 7b4712b8f16..480eb0b1127 100644
--- a/packages/playground/package.json
+++ b/packages/playground/package.json
@@ -5,7 +5,7 @@
   "scripts": {
     "clean": "rescript clean",
     "test": "node ./playground_test.cjs",
-    "build": "rescript clean && rescript-legacy build && node scripts/generate_cmijs.mjs && rollup -c && touch .buildstamp",
+    "build": "rescript clean && rescript build && node scripts/generate_cmijs.mjs && rollup -c && touch .buildstamp",
     "upload-bundle": "node scripts/upload_bundle.mjs",
     "serve-bundle": "node serve-bundle.mjs"
   },
diff --git a/packages/playground/scripts/generate_cmijs.mjs b/packages/playground/scripts/generate_cmijs.mjs
index 034d7bb6a02..4a84d293f09 100644
--- a/packages/playground/scripts/generate_cmijs.mjs
+++ b/packages/playground/scripts/generate_cmijs.mjs
@@ -24,7 +24,7 @@ import {
 } from "./common.mjs";
 
 exec("yarn rescript clean");
-exec("yarn rescript-legacy build");
+exec("yarn rescript build");
 
 // We need to build the compiler's builtin modules as a separate cmij.
 // Otherwise we can't use them for compilation within the playground.
diff --git a/scripts/res/package.json b/scripts/res/package.json
index ae5cfdaec1a..ed2a8a2a3a0 100644
--- a/scripts/res/package.json
+++ b/scripts/res/package.json
@@ -3,9 +3,9 @@
   "type": "module",
   "private": true,
   "scripts": {
-    "build": "rescript-legacy build",
+    "build": "rescript build",
     "clean": "rescript clean",
-    "dev": "rescript-legacy -w",
+    "dev": "rescript watch",
     "apidocs:generate": "yarn build && node GenApiDocs.res.js"
   },
   "dependencies": {
diff --git a/tests/analysis_tests/tests-generic-jsx-transform/package.json b/tests/analysis_tests/tests-generic-jsx-transform/package.json
index 8d369b180d7..ad6fe33fc00 100644
--- a/tests/analysis_tests/tests-generic-jsx-transform/package.json
+++ b/tests/analysis_tests/tests-generic-jsx-transform/package.json
@@ -2,8 +2,8 @@
   "name": "@tests/generic-jsx-transform",
   "private": true,
   "scripts": {
-    "build": "rescript-legacy build",
-    "clean": "rescript-legacy clean"
+    "build": "rescript build",
+    "clean": "rescript clean"
   },
   "dependencies": {
     "rescript": "workspace:^"
diff --git a/tests/analysis_tests/tests-generic-jsx-transform/rescript.json b/tests/analysis_tests/tests-generic-jsx-transform/rescript.json
index 1580c61aa5a..6a2a13610c8 100644
--- a/tests/analysis_tests/tests-generic-jsx-transform/rescript.json
+++ b/tests/analysis_tests/tests-generic-jsx-transform/rescript.json
@@ -1,11 +1,12 @@
 {
-  "name": "test-generic-jsx-transform",
+  "name": "@tests/generic-jsx-transform",
   "sources": [
     {
       "dir": "src",
       "subdirs": true
     }
   ],
-  "compiler-flags": ["-w -33-44-8"],
+  "compiler-flags": ["-w -33-44-8-26-27-110"],
+  "package-specs": [{ "module": "commonjs", "in-source": false }],
   "jsx": { "module": "GenericJsx" }
 }
diff --git a/tests/analysis_tests/tests-incremental-typechecking/Makefile b/tests/analysis_tests/tests-incremental-typechecking/Makefile
index c0055793d2a..6abbf0dd984 100644
--- a/tests/analysis_tests/tests-incremental-typechecking/Makefile
+++ b/tests/analysis_tests/tests-incremental-typechecking/Makefile
@@ -1,7 +1,7 @@
 SHELL = /bin/bash
 
 build:
-	yarn build > /dev/null || true
+	yarn build > /dev/null 2>&1 || true
 
 test: build
 	./test.sh
diff --git a/tests/analysis_tests/tests-incremental-typechecking/package.json b/tests/analysis_tests/tests-incremental-typechecking/package.json
index 840385ceccd..f36825de87b 100644
--- a/tests/analysis_tests/tests-incremental-typechecking/package.json
+++ b/tests/analysis_tests/tests-incremental-typechecking/package.json
@@ -2,8 +2,8 @@
   "name": "@tests/incremental-typechecking",
   "private": true,
   "scripts": {
-    "build": "rescript-legacy build",
-    "clean": "rescript-legacy clean"
+    "build": "rescript build",
+    "clean": "rescript clean"
   },
   "dependencies": {
     "rescript": "workspace:^"
diff --git a/tests/analysis_tests/tests-incremental-typechecking/rescript.json b/tests/analysis_tests/tests-incremental-typechecking/rescript.json
index 1580c61aa5a..d786f5a4be8 100644
--- a/tests/analysis_tests/tests-incremental-typechecking/rescript.json
+++ b/tests/analysis_tests/tests-incremental-typechecking/rescript.json
@@ -1,11 +1,11 @@
 {
-  "name": "test-generic-jsx-transform",
+  "name": "@tests/incremental-typechecking",
   "sources": [
     {
       "dir": "src",
       "subdirs": true
     }
   ],
-  "compiler-flags": ["-w -33-44-8"],
+  "compiler-flags": ["-w -33-44-8-26-27-110"],
   "jsx": { "module": "GenericJsx" }
 }
diff --git a/tests/analysis_tests/tests-reanalyze/termination/package.json b/tests/analysis_tests/tests-reanalyze/termination/package.json
index a52dc030b62..01bd0f1d8b6 100644
--- a/tests/analysis_tests/tests-reanalyze/termination/package.json
+++ b/tests/analysis_tests/tests-reanalyze/termination/package.json
@@ -2,8 +2,8 @@
   "name": "@tests/reanalyze-termination",
   "private": true,
   "scripts": {
-    "build": "rescript-legacy build",
-    "clean": "rescript-legacy clean"
+    "build": "rescript build",
+    "clean": "rescript clean"
   },
   "dependencies": {
     "rescript": "workspace:^"
diff --git a/tests/analysis_tests/tests-reanalyze/termination/rescript.json b/tests/analysis_tests/tests-reanalyze/termination/rescript.json
index 3c8e376d609..a3afd79ad59 100644
--- a/tests/analysis_tests/tests-reanalyze/termination/rescript.json
+++ b/tests/analysis_tests/tests-reanalyze/termination/rescript.json
@@ -4,7 +4,7 @@
     "suppress": [],
     "unsuppress": []
   },
-  "name": "arnold",
+  "name": "@tests/reanalyze-termination",
   "dependencies": [],
   "sources": [
     {
diff --git a/tests/analysis_tests/tests-reanalyze/termination/src/TestCyberTruck.res b/tests/analysis_tests/tests-reanalyze/termination/src/TestCyberTruck.res
index e2c6be68c79..413179ad533 100644
--- a/tests/analysis_tests/tests-reanalyze/termination/src/TestCyberTruck.res
+++ b/tests/analysis_tests/tests-reanalyze/termination/src/TestCyberTruck.res
@@ -145,7 +145,7 @@ module Parser = {
     | Asterisk => "*"
     | Eof => "Eof"
     | Lparen => "("
-    | Int(n) => string_of_int(n)
+    | Int(n) => Int.toString(n)
     | Plus => "+"
     | Rparen => ")"
     }
@@ -256,7 +256,7 @@ module UITermination = {
 
   let counter = (state: state, ~setState: setState) => {
     setState(~f=initState)
-    div(~text=string_of_int(state), ~onClick=() => setState(~f=increment))
+    div(~text=Int.toString(state), ~onClick=() => setState(~f=increment))
   }
 
   @progress(initState)
@@ -265,7 +265,7 @@ module UITermination = {
     | None => ()
     | Some(newState) => ignore(counterCompiled(newState))
     }
-    ignore(string_of_int(state))
+    ignore(Int.toString(state))
   }
 
   and onClick1 = state =>
@@ -276,7 +276,7 @@ module UITermination = {
 
   let countRenders = (state: state, ~setState: setState) => {
     setState(~f=increment)
-    div(~text="I have been rendered " ++ (string_of_int(state) ++ " times"), ~onClick=nothing)
+    div(~text="I have been rendered " ++ (Int.toString(state) ++ " times"), ~onClick=nothing)
   }
 
   @progress(initState)
@@ -285,7 +285,7 @@ module UITermination = {
     | None => ()
     | Some(newState) => ignore(countRendersCompiled(newState))
     }
-    ignore("I have been rendered " ++ (string_of_int(state) ++ " times"))
+    ignore("I have been rendered " ++ (Int.toString(state) ++ " times"))
   }
 }
 
diff --git a/tests/analysis_tests/tests/package.json b/tests/analysis_tests/tests/package.json
index 8b90f6f72ee..c5301890991 100644
--- a/tests/analysis_tests/tests/package.json
+++ b/tests/analysis_tests/tests/package.json
@@ -2,8 +2,8 @@
   "name": "@tests/analysis",
   "private": true,
   "scripts": {
-    "build": "rescript-legacy build",
-    "clean": "rescript-legacy clean"
+    "build": "rescript build",
+    "clean": "rescript clean"
   },
   "dependencies": {
     "@rescript/react": "link:../../dependencies/rescript-react",
diff --git a/tests/analysis_tests/tests/rescript.json b/tests/analysis_tests/tests/rescript.json
index 4a4757d332a..f87f7d538a2 100644
--- a/tests/analysis_tests/tests/rescript.json
+++ b/tests/analysis_tests/tests/rescript.json
@@ -1,5 +1,5 @@
 {
-  "name": "test",
+  "name": "@tests/analysis",
   "reanalyze": {
     "analysis": ["dce"]
   },
@@ -9,9 +9,10 @@
       "subdirs": true
     }
   ],
-  "compiler-flags": ["-w -33-44-8"],
+  "compiler-flags": ["-w -33-44-8-26-27-110"],
   "dependencies": ["@rescript/react"],
   "jsx": { "version": 4 },
+  "package-specs": [{ "module": "commonjs", "in-source": false }],
   "suffix": ".res.js",
   "editor": {
     "autocomplete": {
diff --git a/tests/docstring_tests/package.json b/tests/docstring_tests/package.json
index dcd60a34cee..dfefbd30bea 100644
--- a/tests/docstring_tests/package.json
+++ b/tests/docstring_tests/package.json
@@ -3,7 +3,7 @@
   "type": "module",
   "private": true,
   "scripts": {
-    "build": "rescript-legacy build",
+    "build": "rescript build",
     "clean": "rescript clean",
     "dev": "rescript -w"
   },
diff --git a/tests/gentype_tests/stdlib-no-shims/package.json b/tests/gentype_tests/stdlib-no-shims/package.json
index d23bc455a4f..fe8642afcfc 100644
--- a/tests/gentype_tests/stdlib-no-shims/package.json
+++ b/tests/gentype_tests/stdlib-no-shims/package.json
@@ -2,7 +2,7 @@
   "name": "@tests/gentype-stdlib-no-shims",
   "private": true,
   "scripts": {
-    "build": "rescript-legacy build",
+    "build": "rescript build",
     "clean": "rescript clean",
     "typecheck": "tsc"
   },
diff --git a/tests/gentype_tests/typescript-react-example/package.json b/tests/gentype_tests/typescript-react-example/package.json
index 273cfe8f8f7..689d8373610 100644
--- a/tests/gentype_tests/typescript-react-example/package.json
+++ b/tests/gentype_tests/typescript-react-example/package.json
@@ -2,8 +2,8 @@
   "name": "@tests/gentype-react-example",
   "private": true,
   "scripts": {
-    "start": "rescript-legacy build -w",
-    "build": "rescript-legacy build",
+    "start": "rescript build -w",
+    "build": "rescript build",
     "clean": "rescript clean",
     "typecheck": "tsc",
     "check": "biome check --changed --no-errors-on-unmatched ."
diff --git a/tests/package_tests/installation_test/package.json b/tests/package_tests/installation_test/package.json
new file mode 100644
index 00000000000..cc750656a79
--- /dev/null
+++ b/tests/package_tests/installation_test/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "install-test"
+}
\ No newline at end of file
diff --git a/tests/tools_tests/package.json b/tests/tools_tests/package.json
index 46209fd6de9..3d25d4c6cc3 100644
--- a/tests/tools_tests/package.json
+++ b/tests/tools_tests/package.json
@@ -2,7 +2,7 @@
   "name": "@tests/tools",
   "private": true,
   "scripts": {
-    "build": "rescript-legacy build -warn-error -3",
+    "build": "rescript build",
     "clean": "rescript clean",
     "dev": "rescript -w"
   },
diff --git a/tests/tools_tests/rescript.json b/tests/tools_tests/rescript.json
index 3ed41da9887..c9936473469 100644
--- a/tests/tools_tests/rescript.json
+++ b/tests/tools_tests/rescript.json
@@ -8,6 +8,9 @@
     "module": "esmodule",
     "in-source": true
   },
+  "warnings": {
+    "error": "-3"
+  },
   "suffix": ".res.js",
   "dependencies": ["@rescript/react"]
 }