diff --git a/apps/docs/content/docs/en/workflows/blocks/pi.mdx b/apps/docs/content/docs/en/workflows/blocks/pi.mdx
index dbe3a59c40a..b502d34e459 100644
--- a/apps/docs/content/docs/en/workflows/blocks/pi.mdx
+++ b/apps/docs/content/docs/en/workflows/blocks/pi.mdx
@@ -211,7 +211,7 @@ The one case neither layer can rescue is a *first* prompt that already exceeds t
 
 ### Create PR [#setup-cloud-pr]
 
-Create PR runs in a sandbox image with the Pi CLI and git baked in.
+Create PR runs in a sandbox image with the Pi CLI, Git, Node.js, and Bun baked in. Repository dependencies are not preinstalled; Pi can run `bun install` when a repository needs them.
 
 1. **Enable sandbox execution.** On self-hosted Sim, set `E2B_ENABLED=true`, `E2B_API_KEY`, `E2B_PI_TEMPLATE_ID` (the Pi template id), and `NEXT_PUBLIC_E2B_ENABLED=true` (this reveals Create PR, Update PR, and Review Code in the UI). Build the template with `bun run apps/sim/scripts/build-pi-e2b-template.ts`. These modes stay hidden until `NEXT_PUBLIC_E2B_ENABLED` is set.
 
diff --git a/apps/sim/scripts/build-pi-daytona-snapshot.ts b/apps/sim/scripts/build-pi-daytona-snapshot.ts
index 99cce3bf645..e746ab92ac7 100644
--- a/apps/sim/scripts/build-pi-daytona-snapshot.ts
+++ b/apps/sim/scripts/build-pi-daytona-snapshot.ts
@@ -28,9 +28,10 @@ import { Daytona, Image } from '@daytona/sdk'
 import { getErrorMessage } from '@sim/utils/errors'
 import {
   PI_APT,
+  PI_BUN_VERSION_ASSERT,
+  PI_GLOBAL_NPM_PACKAGES,
   PI_NODE_MAJOR,
   PI_NODE_VERSION_ASSERT,
-  PI_NPM,
   PI_SANDBOX_CPU_COUNT,
   PI_SANDBOX_MEMORY_GB,
 } from '@/scripts/pi-sandbox-packages'
@@ -63,7 +64,8 @@ export const piImage = Image.base(BASE_IMAGE).runCommands(
   // ships an older Node fails here rather than at the first agent run.
   `apt-get update && curl -fsSL https://deb.nodesource.com/setup_${PI_NODE_MAJOR}.x | bash - && ${APT_PREFIX} nodejs && rm -rf /var/lib/apt/lists/* && ${PI_NODE_VERSION_ASSERT}`,
   `apt-get update && ${APT_PREFIX} ${PI_APT.join(' ')} && rm -rf /var/lib/apt/lists/*`,
-  `npm install -g ${PI_NPM.join(' ')}`,
+  `npm install -g ${PI_GLOBAL_NPM_PACKAGES.join(' ')}`,
+  PI_BUN_VERSION_ASSERT,
   // The clone target. E2B's base ships a world-writable /code; Pi writes to
   // /workspace (cloud-review-tools.ts:14), so create it explicitly.
   'mkdir -p /workspace'
diff --git a/apps/sim/scripts/build-pi-e2b-template.ts b/apps/sim/scripts/build-pi-e2b-template.ts
index 53283566ba6..9ab2fa2e52b 100644
--- a/apps/sim/scripts/build-pi-e2b-template.ts
+++ b/apps/sim/scripts/build-pi-e2b-template.ts
@@ -19,9 +19,10 @@
 import { defaultBuildLogger, Template, waitForTimeout } from '@e2b/code-interpreter'
 import {
   PI_APT,
+  PI_BUN_VERSION_ASSERT,
+  PI_GLOBAL_NPM_PACKAGES,
   PI_NODE_MAJOR,
   PI_NODE_VERSION_ASSERT,
-  PI_NPM,
   PI_SANDBOX_CPU_COUNT,
   PI_SANDBOX_MEMORY_MB,
 } from '@/scripts/pi-sandbox-packages'
@@ -38,7 +39,8 @@ const piTemplate = Template()
   .fromTemplate('code-interpreter-v1')
   .runCmd(INSTALL_NODE_COMMAND, { user: 'root' })
   .aptInstall([...PI_APT])
-  .npmInstall([...PI_NPM], { g: true })
+  .npmInstall([...PI_GLOBAL_NPM_PACKAGES], { g: true })
+  .runCmd(PI_BUN_VERSION_ASSERT, { user: 'root' })
   .setStartCmd(START_COMMAND, waitForTimeout(1_000))
 
 async function main() {
diff --git a/apps/sim/scripts/pi-sandbox-packages.ts b/apps/sim/scripts/pi-sandbox-packages.ts
index 90f3567219b..59d7c29632d 100644
--- a/apps/sim/scripts/pi-sandbox-packages.ts
+++ b/apps/sim/scripts/pi-sandbox-packages.ts
@@ -13,8 +13,12 @@
  * owns the Pi block.
  */
 
-/** Exact first-party Pi versions mirrored from bun.lock — image builds run npm independently. */
-export const PI_NPM = [
+/** Bun version mirrored from the root packageManager field. */
+export const PI_BUN_VERSION = '1.3.13'
+
+/** Exact global package versions mirrored from package.json and bun.lock. */
+export const PI_GLOBAL_NPM_PACKAGES = [
+  `bun@${PI_BUN_VERSION}`,
   '@earendil-works/pi-coding-agent@0.80.10',
   '@earendil-works/pi-agent-core@0.80.10',
   '@earendil-works/pi-ai@0.80.10',
@@ -51,6 +55,9 @@ export const PI_NODE_MAJOR = 22
 export const PI_NODE_VERSION_ASSERT =
   'node -e "const [major, minor] = process.versions.node.split(\'.\').map(Number); if (major < 22 || (major === 22 && minor < 19)) process.exit(1)"'
 
+/** Fails the build loudly if the sandbox does not contain the repository's Bun version. */
+export const PI_BUN_VERSION_ASSERT = `test "$(bun --version)" = "${PI_BUN_VERSION}"`
+
 /**
  * The review tools run `python3 /workspace/sim-review-tools.py`
  * (`cloud-review-tools.ts:15`). E2B's `code-interpreter-v1` base ships Python, so