diff --git a/.github/workflows/shell-tool-mcp-ci.yml b/.github/workflows/shell-tool-mcp-ci.yml
index bea88ad891..739cc6e409 100644
--- a/.github/workflows/shell-tool-mcp-ci.yml
+++ b/.github/workflows/shell-tool-mcp-ci.yml
@@ -35,15 +35,6 @@ jobs:
           node-version: ${{ env.NODE_VERSION }}
           cache: "pnpm"
 
-      - name: Enable Corepack
-        run: corepack enable
-
-      - name: Activate pnpm from package.json
-        run: corepack prepare --activate
-
-      - name: Verify pnpm version
-        run: pnpm --version
-
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
 
diff --git a/.github/workflows/shell-tool-mcp.yml b/.github/workflows/shell-tool-mcp.yml
index 39f176cbf4..d6c85d9ddc 100644
--- a/.github/workflows/shell-tool-mcp.yml
+++ b/.github/workflows/shell-tool-mcp.yml
@@ -351,15 +351,6 @@ jobs:
         with:
           node-version: ${{ env.NODE_VERSION }}
 
-      - name: Enable Corepack
-        run: corepack enable
-
-      - name: Activate pnpm from package.json
-        run: corepack prepare --activate
-
-      - name: Verify pnpm version
-        run: pnpm --version
-
       - name: Install JavaScript dependencies
         run: pnpm install --frozen-lockfile
 
@@ -460,15 +451,6 @@ jobs:
           registry-url: https://registry.npmjs.org
           scope: "@openai"
 
-      - name: Enable Corepack
-        run: corepack enable
-
-      - name: Activate pnpm from package.json
-        run: corepack prepare --activate
-
-      - name: Verify pnpm version
-        run: pnpm --version
-
       - name: Download npm tarball
         uses: actions/download-artifact@v7
         with:
diff --git a/PNPM.md b/PNPM.md
deleted file mode 100644
index 9f05e39cf8..0000000000
--- a/PNPM.md
+++ /dev/null
@@ -1,70 +0,0 @@
-# Migration to pnpm
-
-This project has been migrated from npm to pnpm to improve dependency management and developer experience.
-
-## Why pnpm?
-
-- **Faster installation**: pnpm is significantly faster than npm and yarn
-- **Disk space savings**: pnpm uses a content-addressable store to avoid duplication
-- **Phantom dependency prevention**: pnpm creates a strict node_modules structure
-- **Native workspaces support**: simplified monorepo management
-
-## How to use pnpm
-
-### Installation
-
-```bash
-# Global installation of pnpm
-npm install -g pnpm@10.28.2
-
-# Or with corepack (available with Node.js 22+)
-corepack enable
-corepack prepare pnpm@10.8.1 --activate
-```
-
-### Common commands
-
-| npm command     | pnpm equivalent  |
-| --------------- | ---------------- |
-| `npm install`   | `pnpm install`   |
-| `npm run build` | `pnpm run build` |
-| `npm test`      | `pnpm test`      |
-| `npm run lint`  | `pnpm run lint`  |
-
-### Workspace-specific commands
-
-| Action                                     | Command                                  |
-| ------------------------------------------ | ---------------------------------------- |
-| Run a command in a specific package        | `pnpm --filter @openai/codex run build`  |
-| Install a dependency in a specific package | `pnpm --filter @openai/codex add lodash` |
-| Run a command in all packages              | `pnpm -r run test`                       |
-
-## Monorepo structure
-
-```
-codex/
-├── pnpm-workspace.yaml    # Workspace configuration
-├── .npmrc                 # pnpm configuration
-├── package.json           # Root dependencies and scripts
-├── codex-cli/             # Main package
-│   └── package.json       # codex-cli specific dependencies
-└── docs/                  # Documentation (future package)
-```
-
-## Configuration files
-
-- **pnpm-workspace.yaml**: Defines the packages included in the monorepo
-- **.npmrc**: Configures pnpm behavior
-- **Root package.json**: Contains shared scripts and dependencies
-
-## CI/CD
-
-CI/CD workflows have been updated to use pnpm instead of npm. Make sure your CI environments use pnpm 10.28.2 or higher.
-
-## Known issues
-
-If you encounter issues with pnpm, try the following solutions:
-
-1. Remove the `node_modules` folder and `pnpm-lock.yaml` file, then run `pnpm install`
-2. Make sure you're using pnpm 10.28.2 or higher
-3. Verify that Node.js 22 or higher is installed
diff --git a/codex-cli/package.json b/codex-cli/package.json
index b83309e42b..3d1a2dcc2c 100644
--- a/codex-cli/package.json
+++ b/codex-cli/package.json
@@ -17,5 +17,6 @@
     "type": "git",
     "url": "git+https://github.com/openai/codex.git",
     "directory": "codex-cli"
-  }
+  },
+  "packageManager": "pnpm@10.28.2+sha512.41872f037ad22f7348e3b1debbaf7e867cfd448f2726d9cf74c08f19507c31d2c8e7a11525b983febc2df640b5438dee6023ebb1f84ed43cc2d654d2bc326264"
 }
diff --git a/codex-rs/responses-api-proxy/npm/package.json b/codex-rs/responses-api-proxy/npm/package.json
index f3956a77d6..d72b60e218 100644
--- a/codex-rs/responses-api-proxy/npm/package.json
+++ b/codex-rs/responses-api-proxy/npm/package.json
@@ -17,5 +17,6 @@
     "type": "git",
     "url": "git+https://github.com/openai/codex.git",
     "directory": "codex-rs/responses-api-proxy/npm"
-  }
+  },
+  "packageManager": "pnpm@10.28.2+sha512.41872f037ad22f7348e3b1debbaf7e867cfd448f2726d9cf74c08f19507c31d2c8e7a11525b983febc2df640b5438dee6023ebb1f84ed43cc2d654d2bc326264"
 }
diff --git a/sdk/typescript/package.json b/sdk/typescript/package.json
index 55ecd1abf3..ab29c3fcec 100644
--- a/sdk/typescript/package.json
+++ b/sdk/typescript/package.json
@@ -62,5 +62,6 @@
     "typescript-eslint": "^8.45.0",
     "zod": "^3.24.2",
     "zod-to-json-schema": "^3.24.6"
-  }
+  },
+  "packageManager": "pnpm@10.28.2+sha512.41872f037ad22f7348e3b1debbaf7e867cfd448f2726d9cf74c08f19507c31d2c8e7a11525b983febc2df640b5438dee6023ebb1f84ed43cc2d654d2bc326264"
 }
diff --git a/shell-tool-mcp/package.json b/shell-tool-mcp/package.json
index c6dfcd7a55..24798b2f6e 100644
--- a/shell-tool-mcp/package.json
+++ b/shell-tool-mcp/package.json
@@ -3,7 +3,6 @@
   "version": "0.0.0-dev",
   "description": "Codex MCP server for the shell tool with patched Bash and exec wrappers.",
   "license": "Apache-2.0",
-  "packageManager": "pnpm@10.28.2+sha512.41872f037ad22f7348e3b1debbaf7e867cfd448f2726d9cf74c08f19507c31d2c8e7a11525b983febc2df640b5438dee6023ebb1f84ed43cc2d654d2bc326264",
   "bin": {
     "codex-shell-tool-mcp": "bin/mcp-server.js"
   },