diff --git a/.claude-plugin/plugin.json b/.claude-plugin/plugin.json
index 77df2b6..68c9c0d 100644
--- a/.claude-plugin/plugin.json
+++ b/.claude-plugin/plugin.json
@@ -1,6 +1,6 @@
 {
   "name": "code-mode",
-  "version": "0.12.16",
+  "version": "0.12.17",
   "description": "Code mode for MCP: the model writes one JavaScript program that calls MCP tools in a sandbox, instead of one tool call per step.",
   "types": "./types/index.d.ts",
   "author": {
diff --git a/hooks/hints.ts b/hooks/hints.ts
index 3cfd79e..0c7b676 100644
--- a/hooks/hints.ts
+++ b/hooks/hints.ts
@@ -13,6 +13,7 @@
 // its body is that one hint. A change proposal is a removal with the new
 // text of the hint in `replace`.
 
+import { normalizePath } from './paths'
 import { splitToolName } from './protocol'
 
 export type HintScope = 'bundled' | 'user' | 'project'
@@ -494,13 +495,7 @@ export const staleDecisionKeys = (keys: readonly string[], key: string, max = MA
 export const resolvePath = (path: string, home: string, cwd: string): string => {
   const full =
     path === '~' || path.startsWith('~/') ? home + path.slice(1) : path.startsWith('/') ? path : `${cwd}/${path}`
-  const parts: string[] = []
-  for (const part of full.split('/')) {
-    if (part === '' || part === '.') continue
-    if (part === '..') parts.pop()
-    else parts.push(part)
-  }
-  return `/${parts.join('/')}`
+  return normalizePath(full)
 }
 
 /** True when `path` is `dir` or inside it (both absolute and normalized). */
diff --git a/hooks/paths.ts b/hooks/paths.ts
index 87670f4..8d28a19 100644
--- a/hooks/paths.ts
+++ b/hooks/paths.ts
@@ -7,8 +7,23 @@ const APP = 'code-mode'
 const HINTS = 'hints'
 const FUNCTIONS = 'functions'
 
-/** A path in code-mode's folder under `root`: HOME or the project root. */
-export const codeModePath = (root: string, ...parts: string[]): string => [root, '.claude', APP, ...parts].join('/')
+/** An absolute path with empty, `.` and `..` parts resolved. */
+export const normalizePath = (path: string): string => {
+  const parts: string[] = []
+  for (const part of path.split('/')) {
+    if (part === '' || part === '.') continue
+    if (part === '..') parts.pop()
+    else parts.push(part)
+  }
+  return `/${parts.join('/')}`
+}
+
+/**
+ * A path in code-mode's folder under `root`: HOME or the project root. It is
+ * normalized, as isUnder needs: HOME can end in a slash or hold a double one.
+ */
+export const codeModePath = (root: string, ...parts: string[]): string =>
+  normalizePath([root, '.claude', APP, ...parts].join('/'))
 
 /** The hint folder under HOME or the project root. */
 export const hintsFolder = (root: string): string => codeModePath(root, HINTS)
@@ -25,8 +40,12 @@ export const functionsFolder = (home: string): string => codeModePath(home, FUNC
  * where Claude Code installed it, under HOME. A folder loaded with --plugin-dir
  * is the person's own checkout, which they edit.
  */
-export const guardedDirs = (home: string, project: string, pluginRoot = ''): string[] => [
-  ...(home ? [hintsFolder(home), functionsFolder(home)] : []),
-  ...(project ? [hintsFolder(project)] : []),
-  ...(home && pluginRoot.startsWith(`${home}/.claude/plugins/`) ? [pluginRoot] : []),
-]
+export const guardedDirs = (home: string, project: string, pluginRoot = ''): string[] => {
+  const plugin = normalizePath(pluginRoot)
+  const plugins = normalizePath(`${home}/.claude/plugins`)
+  return [
+    ...(home ? [hintsFolder(home), functionsFolder(home)] : []),
+    ...(project ? [hintsFolder(project)] : []),
+    ...(home && plugin.startsWith(`${plugins}/`) ? [plugin] : []),
+  ]
+}
diff --git a/tests/hints.test.ts b/tests/hints.test.ts
index 046a20d..4221ad9 100644
--- a/tests/hints.test.ts
+++ b/tests/hints.test.ts
@@ -266,6 +266,12 @@ describe('hints in the tools', () => {
     expect(text).toContain('Mail hint body.')
   })
 
+  test('a user hint loads when HOME ends in a slash', async ($, on) => {
+    const { env } = await approvedHome(on, hintFile, { [MAIL]: 'claude.ai Mail' })
+    env.HOME = `${HOME}/`
+    expect(textOf(await $.tool.call({ tool: TOOL.search_tools, query: 'send' }))).toContain('Mail hint body.')
+  })
+
   test('search_tools finds hints by identify when the server is named by UUID', async ($, on) => {
     await approvedHome(
       on,
@@ -1526,9 +1532,9 @@ describe('the hint-file guard', () => {
     expect(isUnder('/a/bc', '/a/b')).toBe(false)
   })
 
-  const session = (on: On) => {
-    fakeHome(on, {})
-    on('session.root', () => ({ value: '/repo' }))
+  const session = (on: On, home = HOME, root = '/repo') => {
+    fakeHome(on, {}).env.HOME = home
+    on('session.root', () => ({ value: root }))
     on('session.cwd', () => ({ value: '/repo' }))
     // stands for the file tools: a call that gets past the guard is written
     on('tool.call', { tool: 'Write' }, () => ({ result: 'written' }))
@@ -1571,6 +1577,32 @@ describe('the hint-file guard', () => {
     })
   }
 
+  // HOME and the project root as the environment gives them, with a trailing
+  // or double slash; the folders do not exist yet, so no real path helps.
+  for (const home of ['/home/u/', '/', '/home//u']) {
+    test(`guards the folders when HOME is ${home}`, async ($, on) => {
+      session(on, home, '/repo/')
+      for (const file_path of [
+        '~/.claude/code-mode/hints/x.md',
+        '~/.claude/code-mode/functions/x.md',
+        '/repo/.claude/code-mode/hints/x.md',
+      ])
+        expect(textOf(await $.tool.call({ tool: 'Write', file_path, content: 'x' }))).toContain(
+          'hint files and saved functions steer the model',
+        )
+    })
+  }
+
+  test('guardedDirs normalizes its roots', () => {
+    const installed = '/home/u/.claude/plugins/cache/code-mode/1.0.0'
+    expect(guardedDirs('/home//u/', '/repo/', `${installed}/`)).toEqual([
+      '/home/u/.claude/code-mode/hints',
+      '/home/u/.claude/code-mode/functions',
+      '/repo/.claude/code-mode/hints',
+      installed,
+    ])
+  })
+
   test('lets other files through', async ($, on) => {
     session(on)
     expect(textOf(await $.tool.call({ tool: 'Write', file_path: '/repo/src/a.ts', content: 'x' }))).toBe('written')