diff --git a/packages/devframe/scripts/check-client-dist.ts b/packages/devframe/scripts/check-client-dist.ts
new file mode 100644
index 0000000..61f7bbe
--- /dev/null
+++ b/packages/devframe/scripts/check-client-dist.ts
@@ -0,0 +1,114 @@
+import { readFile } from 'node:fs/promises'
+import { dirname, relative, resolve } from 'node:path'
+import { findDynamicImports, findExports, findStaticImports } from 'mlly'
+
+interface ForbiddenRule {
+  name: string
+  match: (specifier: string) => boolean
+}
+
+const FORBIDDEN: ForbiddenRule[] = [
+  { name: 'ws', match: id => id === 'ws' || id.startsWith('ws/') },
+  { name: 'h3', match: id => id === 'h3' || id.startsWith('h3/') },
+  { name: 'node:* builtin', match: id => id.startsWith('node:') },
+  { name: 'devframe/rpc/transports/*', match: id => id.startsWith('devframe/rpc/transports/') },
+  { name: 'devframe/node*', match: id => id === 'devframe/node' || id.startsWith('devframe/node/') },
+  { name: 'devframe/adapters/*', match: id => id.startsWith('devframe/adapters/') },
+  { name: 'devframe/helpers/*', match: id => id.startsWith('devframe/helpers/') },
+  { name: 'devframe/recipes/*', match: id => id.startsWith('devframe/recipes/') },
+  { name: 'devframe/utils/launch-editor', match: id => id === 'devframe/utils/launch-editor' },
+  { name: 'devframe/utils/open', match: id => id === 'devframe/utils/open' },
+  { name: 'devframe/utils/serve-static', match: id => id === 'devframe/utils/serve-static' },
+]
+
+interface ScannedSpecifiers {
+  static: string[]
+  dynamic: string[]
+}
+
+interface Violation {
+  file: string
+  specifier: string
+  rule: string
+}
+
+async function scanSpecifiers(file: string): Promise<ScannedSpecifiers> {
+  const code = await readFile(file, 'utf8')
+  const staticIds = new Set<string>()
+  for (const i of findStaticImports(code))
+    staticIds.add(i.specifier)
+  for (const e of findExports(code)) {
+    if (e.specifier)
+      staticIds.add(e.specifier)
+  }
+  const dynamicIds = new Set<string>()
+  for (const d of findDynamicImports(code)) {
+    // Only consider plain string expressions; ignore variable/template imports.
+    const match = d.expression.match(/^\s*['"]([^'"]+)['"]\s*$/)
+    if (match?.[1])
+      dynamicIds.add(match[1])
+  }
+  return { static: [...staticIds], dynamic: [...dynamicIds] }
+}
+
+export interface CheckClientDistOptions {
+  /** Absolute paths to the client entry chunks to walk from. */
+  entries: string[]
+  /** Used to build relative paths in error messages. */
+  cwd: string
+}
+
+export async function checkClientDist(options: CheckClientDistOptions): Promise<void> {
+  const { entries, cwd } = options
+  const visited = new Set<string>()
+  const violations: Violation[] = []
+
+  async function visit(file: string): Promise<void> {
+    if (visited.has(file))
+      return
+    visited.add(file)
+
+    let scanned: ScannedSpecifiers
+    try {
+      scanned = await scanSpecifiers(file)
+    }
+    catch (err) {
+      throw new Error(`[check-client-dist] Failed to read ${relative(cwd, file)}: ${(err as Error).message}`)
+    }
+
+    // Static imports load eagerly when the file is evaluated — they're the leak
+    // vector this guard exists to catch. Flag any forbidden specifier.
+    for (const id of scanned.static) {
+      const hit = FORBIDDEN.find(r => r.match(id))
+      if (hit)
+        violations.push({ file, specifier: id, rule: hit.name })
+    }
+
+    // Follow both static and dynamic relative imports to discover every chunk
+    // the browser can end up loading. Dynamic specifiers themselves aren't
+    // checked against FORBIDDEN — the chunk they target is, on visit.
+    for (const id of [...scanned.static, ...scanned.dynamic]) {
+      if (id.startsWith('./') || id.startsWith('../')) {
+        const next = resolve(dirname(file), id)
+        await visit(next)
+      }
+    }
+  }
+
+  for (const entry of entries)
+    await visit(entry)
+
+  if (violations.length > 0) {
+    const lines: string[] = ['[check-client-dist] Forbidden server-only imports found in client dist:', '']
+    for (const v of violations) {
+      lines.push(`  ${relative(cwd, v.file)}`)
+      lines.push(`    imports ${JSON.stringify(v.specifier)} (matches forbidden rule: ${v.rule})`)
+    }
+    lines.push('')
+    lines.push(`Scanned ${visited.size} chunks reachable from ${entries.length} client entries.`)
+    lines.push('Client chunks must not statically import server-only modules — see packages/devframe/tsdown.config.ts.')
+    throw new Error(lines.join('\n'))
+  }
+
+  console.log(`[check-client-dist] OK — scanned ${visited.size} chunks reachable from ${entries.length} client entries`)
+}
diff --git a/packages/devframe/tsdown.config.ts b/packages/devframe/tsdown.config.ts
index 9c68fd5..d9d2e31 100644
--- a/packages/devframe/tsdown.config.ts
+++ b/packages/devframe/tsdown.config.ts
@@ -1,102 +1,142 @@
+import { dirname, resolve } from 'node:path'
 import { fileURLToPath } from 'node:url'
-import { resolveSync } from 'mlly'
 import { defineConfig } from 'tsdown'
 
-// Resolve `ohash/crypto` without the `node` condition so the pure-JS digest
-// is bundled. The default resolution honours `node`, which inlines
-// `node:crypto.createHash` into outputs that are later shipped to the
-// browser via the `client` entry.
-const ohashCryptoAgnostic = fileURLToPath(
-  resolveSync('ohash/crypto', { url: import.meta.url, conditions: ['import'] }),
-)
+const here = dirname(fileURLToPath(import.meta.url))
+const distDir = resolve(here, 'dist')
 
-export default defineConfig({
-  alias: {
-    'ohash/crypto': ohashCryptoAgnostic,
-  },
-  entry: {
-    'index': 'src/index.ts',
-    'rpc/index': 'src/rpc/index.ts',
-    'rpc/client': 'src/rpc/client.ts',
-    'rpc/server': 'src/rpc/server.ts',
-    'rpc/transports/ws-client': 'src/rpc/transports/ws-client.ts',
-    'rpc/transports/ws-server': 'src/rpc/transports/ws-server.ts',
-    'types/index': 'src/types/index.ts',
-    'node/index': 'src/node/index.ts',
-    'node/auth': 'src/node/auth/index.ts',
-    'node/internal': 'src/node/internal/index.ts',
-    'constants': 'src/constants.ts',
-    'utils/colors': 'src/utils/colors.ts',
-    'utils/events': 'src/utils/events.ts',
-    'utils/hash': 'src/utils/hash.ts',
-    'utils/human-id': 'src/utils/human-id.ts',
-    'utils/launch-editor': 'src/utils/launch-editor.ts',
-    'utils/nanoid': 'src/utils/nanoid.ts',
-    'utils/open': 'src/utils/open.ts',
-    'utils/promise': 'src/utils/promise.ts',
-    'utils/serve-static': 'src/utils/serve-static.ts',
-    'utils/shared-state': 'src/utils/shared-state.ts',
-    'utils/streaming-channel': 'src/utils/streaming-channel.ts',
-    'utils/structured-clone': 'src/utils/structured-clone.ts',
-    'utils/when': 'src/utils/when.ts',
-    'adapters/cli': 'src/adapters/cli.ts',
-    'adapters/dev': 'src/adapters/dev.ts',
-    'adapters/build': 'src/adapters/build.ts',
-    'helpers/vite': 'src/helpers/vite.ts',
-    'adapters/embedded': 'src/adapters/embedded.ts',
-    'adapters/mcp': 'src/adapters/mcp/index.ts',
-    'client/index': 'src/client/index.ts',
-    'recipes/open-helpers': 'src/recipes/open-helpers.ts',
-  },
-  tsconfig: '../../tsconfig.base.json',
-  clean: true,
-  dts: true,
-  exports: true,
+const tsconfig = '../../tsconfig.base.json'
+
+const deps = {
   // Keep transitive external type graphs out of dts bundling.
   // `vite`/`esbuild`/`postcss` are pulled in via the kit client's
   // `declare module 'vite'` augmentation and contain
   // rolldown-incompatible re-exports that would otherwise fail dts
   // generation with dozens of MISSING_EXPORT errors.
-  deps: {
-    neverBundle: [
-      'vite',
-      'esbuild',
-      'postcss',
-      'rolldown',
-      /^@rolldown\//,
-      /^@oxc-project\//,
-      'terser',
-      '@jridgewell/trace-mapping',
-    ],
-    onlyBundle: [
-      'acorn',
-      'bundle-name',
-      'default-browser',
-      'default-browser-id',
-      'define-lazy-prop',
-      'get-port-please',
-      'immer',
-      'is-docker',
-      'is-in-ssh',
-      'is-inside-container',
-      'is-wsl',
-      'launch-editor',
-      'mlly',
-      'obug',
-      'ohash',
-      'open',
-      'p-limit',
-      'perfect-debounce',
-      'picocolors',
-      'powershell-utils',
-      'run-applescript',
-      'shell-quote',
-      'structured-clone-es',
-      'tinyexec',
-      'ua-parser-modern',
-      'whenexpr',
-      'wsl-utils',
-      'yocto-queue',
-    ],
+  neverBundle: [
+    'vite',
+    'esbuild',
+    'postcss',
+    'rolldown',
+    /^@rolldown\//,
+    /^@oxc-project\//,
+    'terser',
+    '@jridgewell/trace-mapping',
+  ],
+  onlyBundle: [
+    'acorn',
+    'bundle-name',
+    'default-browser',
+    'default-browser-id',
+    'define-lazy-prop',
+    'get-port-please',
+    'immer',
+    'is-docker',
+    'is-in-ssh',
+    'is-inside-container',
+    'is-wsl',
+    'launch-editor',
+    'mlly',
+    'obug',
+    'ohash',
+    'open',
+    'p-limit',
+    'perfect-debounce',
+    'picocolors',
+    'powershell-utils',
+    'run-applescript',
+    'shell-quote',
+    'structured-clone-es',
+    'tinyexec',
+    'ua-parser-modern',
+    'whenexpr',
+    'wsl-utils',
+    'yocto-queue',
+  ],
+}
+
+// Split into two configs so client/agnostic and server entries live in
+// independent rolldown chunk graphs. A single combined build lets rolldown
+// hoist shared helpers into chunks that mix server-only imports like
+// `devframe/rpc/transports/ws-server` or `node:crypto`, which then leak into
+// browser-loaded outputs (e.g. `client/index.mjs`, `utils/hash.mjs`).
+export default defineConfig([
+  // Client / agnostic build — runs first; `clean: true` clears dist/ before
+  // the server build appends to it. Keep this first in the array.
+  {
+    clean: true,
+    platform: 'browser',
+    tsconfig,
+    deps,
+    dts: true,
+    // Force `.mjs` / `.d.mts` extensions to match the server config and the
+    // `packages/devframe/package.json` `exports` map. `platform: 'browser'`
+    // defaults to `.js`, which would break those entry paths.
+    outExtensions: () => ({ js: '.mjs', dts: '.d.mts' }),
+    entry: {
+      'client/index': 'src/client/index.ts',
+      'utils/colors': 'src/utils/colors.ts',
+      'utils/events': 'src/utils/events.ts',
+      'utils/hash': 'src/utils/hash.ts',
+      'utils/human-id': 'src/utils/human-id.ts',
+      'utils/nanoid': 'src/utils/nanoid.ts',
+      'utils/promise': 'src/utils/promise.ts',
+      'utils/shared-state': 'src/utils/shared-state.ts',
+      'utils/streaming-channel': 'src/utils/streaming-channel.ts',
+      'utils/structured-clone': 'src/utils/structured-clone.ts',
+      'utils/when': 'src/utils/when.ts',
+    },
+    hooks: {
+      'build:done': async () => {
+        const { checkClientDist } = await import('./scripts/check-client-dist.ts')
+        await checkClientDist({
+          entries: [
+            resolve(distDir, 'client/index.mjs'),
+            resolve(distDir, 'utils/colors.mjs'),
+            resolve(distDir, 'utils/events.mjs'),
+            resolve(distDir, 'utils/hash.mjs'),
+            resolve(distDir, 'utils/human-id.mjs'),
+            resolve(distDir, 'utils/nanoid.mjs'),
+            resolve(distDir, 'utils/promise.mjs'),
+            resolve(distDir, 'utils/shared-state.mjs'),
+            resolve(distDir, 'utils/streaming-channel.mjs'),
+            resolve(distDir, 'utils/structured-clone.mjs'),
+            resolve(distDir, 'utils/when.mjs'),
+          ],
+          cwd: here,
+        })
+      },
+    },
+  },
+  // Server / node build — `clean: false` so it appends to the client output.
+  {
+    clean: false,
+    platform: 'node',
+    tsconfig,
+    deps,
+    dts: true,
+    entry: {
+      'index': 'src/index.ts',
+      'constants': 'src/constants.ts',
+      'types/index': 'src/types/index.ts',
+      'rpc/index': 'src/rpc/index.ts',
+      'rpc/client': 'src/rpc/client.ts',
+      'rpc/server': 'src/rpc/server.ts',
+      'rpc/transports/ws-client': 'src/rpc/transports/ws-client.ts',
+      'rpc/transports/ws-server': 'src/rpc/transports/ws-server.ts',
+      'node/index': 'src/node/index.ts',
+      'node/auth': 'src/node/auth/index.ts',
+      'node/internal': 'src/node/internal/index.ts',
+      'utils/launch-editor': 'src/utils/launch-editor.ts',
+      'utils/open': 'src/utils/open.ts',
+      'utils/serve-static': 'src/utils/serve-static.ts',
+      'adapters/cli': 'src/adapters/cli.ts',
+      'adapters/dev': 'src/adapters/dev.ts',
+      'adapters/build': 'src/adapters/build.ts',
+      'adapters/embedded': 'src/adapters/embedded.ts',
+      'adapters/mcp': 'src/adapters/mcp/index.ts',
+      'helpers/vite': 'src/helpers/vite.ts',
+      'recipes/open-helpers': 'src/recipes/open-helpers.ts',
+    },
   },
-})
+])
diff --git a/tests/__snapshots__/tsnapi/devframe/rpc/transports/ws-client.snapshot.d.ts b/tests/__snapshots__/tsnapi/devframe/rpc/transports/ws-client.snapshot.d.ts
index 22cde9f..656516d 100644
--- a/tests/__snapshots__/tsnapi/devframe/rpc/transports/ws-client.snapshot.d.ts
+++ b/tests/__snapshots__/tsnapi/devframe/rpc/transports/ws-client.snapshot.d.ts
@@ -1,7 +1,17 @@
 /**
  * Generated by tsnapi — public API snapshot of `devframe/rpc/transports/ws-client`
  */
-// #region Other
-export { createWsRpcChannel }
-export { WsRpcChannelOptions }
+// #region Interfaces
+export interface WsRpcChannelOptions {
+  url: string;
+  onConnected?: (_: Event) => void;
+  onError?: (_: Error) => void;
+  onDisconnected?: (_: CloseEvent) => void;
+  authToken?: string;
+  definitions?: ReadonlyMap<string, Pick<RpcFunctionDefinitionAny, 'jsonSerializable'>>;
+}
+// #endregion
+
+// #region Functions
+export declare function createWsRpcChannel(_: WsRpcChannelOptions): ChannelOptions;
 // #endregion
\ No newline at end of file