diff --git a/.chronus/changes/copilot-remove-build-artifacts-from-npm-2026-7-7-14-35-46.md b/.chronus/changes/copilot-remove-build-artifacts-from-npm-2026-7-7-14-35-46.md
new file mode 100644
index 00000000000..c0e84aa8cbf
--- /dev/null
+++ b/.chronus/changes/copilot-remove-build-artifacts-from-npm-2026-7-7-14-35-46.md
@@ -0,0 +1,17 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/emitter-framework"
+  - "@typespec/http-canonicalization"
+  - "@typespec/http-client"
+  - "@typespec/http-client-js"
+  - "@typespec/http-server-js"
+  - "@typespec/http-specs"
+  - "@typespec/mutator-framework"
+  - "@typespec/protobuf"
+  - "@typespec/spec-api"
+  - "@typespec/spec-coverage-sdk"
+  - "@typespec/spector"
+---
+
+Exclude build artifacts from published packages
\ No newline at end of file
diff --git a/eng/common/scripts/package-files.test.ts b/eng/common/scripts/package-files.test.ts
new file mode 100644
index 00000000000..9db3aa7cebb
--- /dev/null
+++ b/eng/common/scripts/package-files.test.ts
@@ -0,0 +1,19 @@
+import { existsSync, readdirSync, readFileSync } from "node:fs";
+import { join } from "node:path";
+import { expect, it } from "vitest";
+
+it("requires publishable packages to declare their published files", () => {
+  const packagesDir = new URL("../../../packages", import.meta.url);
+  const packagesWithoutFiles = readdirSync(packagesDir, { withFileTypes: true })
+    .filter((entry) => entry.isDirectory())
+    .filter((entry) => {
+      const packageJsonPath = join(packagesDir.pathname, entry.name, "package.json");
+      if (!existsSync(packageJsonPath)) return false;
+
+      const packageJson = JSON.parse(readFileSync(packageJsonPath, "utf-8"));
+      return packageJson.private !== true && packageJson.files === undefined;
+    })
+    .map((entry) => entry.name);
+
+  expect(packagesWithoutFiles).toEqual([]);
+});
diff --git a/packages/emitter-framework/package.json b/packages/emitter-framework/package.json
index d3c61094183..212b1e6c343 100644
--- a/packages/emitter-framework/package.json
+++ b/packages/emitter-framework/package.json
@@ -7,6 +7,9 @@
     "type": "git",
     "url": "git+https://github.com/microsoft/typespec.git"
   },
+  "files": [
+    "dist/**"
+  ],
   "scripts": {
     "build": "alloy build",
     "clean": "rimraf ./dist",
diff --git a/packages/http-canonicalization/package.json b/packages/http-canonicalization/package.json
index 2270a2ef972..4fca5426a0b 100644
--- a/packages/http-canonicalization/package.json
+++ b/packages/http-canonicalization/package.json
@@ -26,6 +26,9 @@
       "import": "./dist/src/index.js"
     }
   },
+  "files": [
+    "dist/**"
+  ],
   "keywords": [],
   "author": "",
   "license": "MIT",
diff --git a/packages/http-client-js/package.json b/packages/http-client-js/package.json
index dfd095a80ab..9e05a5f1256 100644
--- a/packages/http-client-js/package.json
+++ b/packages/http-client-js/package.json
@@ -36,6 +36,10 @@
       "import": "./dist/src/components/index.js"
     }
   },
+  "files": [
+    "dist/**",
+    "!dist/test/**"
+  ],
   "keywords": [
     "typespec",
     "javascript",
diff --git a/packages/http-client/package.json b/packages/http-client/package.json
index 084ed248838..562d5c20d50 100644
--- a/packages/http-client/package.json
+++ b/packages/http-client/package.json
@@ -22,6 +22,11 @@
       "import": "./dist/src/components/index.js"
     }
   },
+  "files": [
+    "lib/*.tsp",
+    "dist/**",
+    "!dist/test/**"
+  ],
   "peerDependencies": {
     "@alloy-js/core": "catalog:",
     "@alloy-js/typescript": "catalog:",
diff --git a/packages/http-server-js/package.json b/packages/http-server-js/package.json
index 80657e3f9f2..00707aa7467 100644
--- a/packages/http-server-js/package.json
+++ b/packages/http-server-js/package.json
@@ -31,6 +31,11 @@
   "bin": {
     "hsjs-scaffold": "./cmd/hsjs-scaffold.mjs"
   },
+  "files": [
+    "dist/**",
+    "cmd/**",
+    "!dist/test/**"
+  ],
   "scripts": {
     "clean": "rimraf ./dist ./temp",
     "build": "pnpm build:helpers && pnpm build:src",
diff --git a/packages/http-specs/package.json b/packages/http-specs/package.json
index c3800fc2371..3a651e7f290 100644
--- a/packages/http-specs/package.json
+++ b/packages/http-specs/package.json
@@ -5,6 +5,11 @@
   "description": "Spec scenarios and mock apis",
   "main": "dist/index.js",
   "type": "module",
+  "files": [
+    "dist/**",
+    "specs/**",
+    "assets/**"
+  ],
   "scripts": {
     "watch": "tsc -p ./tsconfig.build.json --watch",
     "build": "tsc -p ./tsconfig.build.json && pnpm validate-scenarios && pnpm build:smoke",
diff --git a/packages/mutator-framework/package.json b/packages/mutator-framework/package.json
index 23c927bdaae..b2f9c4f37ff 100644
--- a/packages/mutator-framework/package.json
+++ b/packages/mutator-framework/package.json
@@ -26,6 +26,9 @@
       "import": "./dist/src/index.js"
     }
   },
+  "files": [
+    "dist/**"
+  ],
   "keywords": [],
   "author": "",
   "license": "MIT",
diff --git a/packages/protobuf/package.json b/packages/protobuf/package.json
index 3e8ed2d0272..3dcea13b9d7 100644
--- a/packages/protobuf/package.json
+++ b/packages/protobuf/package.json
@@ -29,6 +29,11 @@
   },
   "type": "module",
   "tspMain": "lib/proto.tsp",
+  "files": [
+    "lib/*.tsp",
+    "dist/**",
+    "!dist/test/**"
+  ],
   "scripts": {
     "clean": "rimraf ./dist ./temp",
     "build": "pnpm gen-extern-signature && tsc -p tsconfig.build.json && pnpm lint-typespec-library",
diff --git a/packages/spec-api/package.json b/packages/spec-api/package.json
index ee932b2c7d7..f0e778d54a4 100644
--- a/packages/spec-api/package.json
+++ b/packages/spec-api/package.json
@@ -8,6 +8,9 @@
       "import": "./dist/index.js"
     }
   },
+  "files": [
+    "dist/**"
+  ],
   "scripts": {
     "watch": "tsc -p ./tsconfig.build.json --watch",
     "build": "tsc -p ./tsconfig.build.json",
diff --git a/packages/spec-coverage-sdk/package.json b/packages/spec-coverage-sdk/package.json
index 7c391a29d46..69642b0397d 100644
--- a/packages/spec-coverage-sdk/package.json
+++ b/packages/spec-coverage-sdk/package.json
@@ -4,6 +4,9 @@
   "description": "Spec utility to manage the reported coverage",
   "main": "dist/index.js",
   "type": "module",
+  "files": [
+    "dist/**"
+  ],
   "scripts": {
     "watch": "tsc -p ./tsconfig.build.json --watch",
     "build": "tsc -p ./tsconfig.build.json",
diff --git a/packages/spector/package.json b/packages/spector/package.json
index ef98b4a546a..d1a7121285e 100644
--- a/packages/spector/package.json
+++ b/packages/spector/package.json
@@ -12,6 +12,12 @@
   "bin": {
     "tsp-spector": "./cmd/cli.mjs"
   },
+  "files": [
+    "lib/*.tsp",
+    "dist/**",
+    "cmd/**",
+    "!dist/test/**"
+  ],
   "scripts": {
     "watch": "tsc -p ./tsconfig.build.json --watch",
     "build": "pnpm gen-extern-signature && tsc -p tsconfig.build.json",