diff --git a/docs/agents-and-tools.md b/docs/agents-and-tools.md
index 02ecb3db27..37094bb0d4 100644
--- a/docs/agents-and-tools.md
+++ b/docs/agents-and-tools.md
@@ -38,16 +38,21 @@ and at GET, whatever the client.
 ### Trust gate for repository `.agents` directories
 
 `loadLocalAgents` dynamically imports every `.ts`/`.tsx`/`.js`/`.mjs`/`.cjs`
-file under `{cwd}/.agents` and `{cwd}/../.agents`, and `loadMCPConfigSync`
-reads an `mcp.json` there whose stdio servers are spawned on the first prompt
-with `$VAR` env values filled from the CLI's own environment. Both execute
+file under `{cwd}/.agents` and `{cwd}/../.agents`, except files under
+`skills/`, `scripts/`, `hooks/`, `vendor/`, `node_modules/` or dot-directories
+(support code, not agent definitions). `vendor/` and `hooks/` are reserved
+names: an agent file under either is skipped without a warning, so keep agents
+of your own in another directory. `loadMCPConfigSync` reads an `mcp.json`
+there whose stdio servers are spawned on the first prompt with `$VAR` env
+values filled from the CLI's own environment. Both execute
 repository-supplied code, so cloning a hostile repo and running the CLI inside
 it must not run anything without consent. The CLI therefore gates those two
 repository-scoped directories (`cli/src/utils/agent-dir-trust.ts`):
 
 - **What needs trust**: a directory containing at least one executable agent
-  file (the loader's extension filter, minus `.d.ts` and tests) or an
-  `mcp.json`. A directory holding only `skills/` markdown does not, and
+  file (a file the loader would import: extension filter, minus `.d.ts` and
+  tests, outside skipped directories) or an `mcp.json`. A directory holding
+  only `skills/` markdown does not, and
   `~/.agents` never does (it is the user's own). Skills still load from an
   untrusted directory; only agents and `mcp.json` are withheld.
 - **The prompt**: on an interactive launch (stdin and stdout are TTYs) the CLI
diff --git a/sdk/CHANGELOG.md b/sdk/CHANGELOG.md
index ba741447d8..fb1faaff30 100644
--- a/sdk/CHANGELOG.md
+++ b/sdk/CHANGELOG.md
@@ -4,6 +4,8 @@ All notable changes to the @codebuff/sdk package will be documented in this file
 
 ## [Unreleased]
 
+- `loadLocalAgents` now skips `hooks/` and `vendor/` directories inside `.agents`. A third-party plugin's hook script was imported as an agent, which ran its top-level code; ponytail's `hooks/ponytail-subagent.js` calls `process.exit(0)`, so the CLI exited before the TUI.
+
 - **Security / breaking:** a fresh session no longer imports `process.cwd()/.agents` or its parent `.agents` when no agents were supplied. Agent files are executable modules (importing one runs its top-level code), so a cloned repository's `.agents` ran on the developer's machine before any prompt or approval. Now `agentDefinitions`, when given, is the whole answer: an empty array loads nothing (it used to fall back to the directories above, re-importing what a host's trust gate had just refused). With `agentDefinitions` omitted, only `~/.agents` is loaded, or the directories in the new `agentDirs` option (`run`, `CodebuffClient`, `initialSessionState`, `generateInitialRunState`). To keep loading a repository's agents, pass `agentDirs: [path.join(repo, '.agents')]` once you trust it, or pass `agentDefinitions` from `loadLocalAgents({ agentDirs })`. `loadLocalAgents()` called with no directories still searches the old defaults. A string agent id that came only from a repository `.agents` file is no longer found locally and may resolve from the `codebuff/<id>` registry; set `disableAgentRegistry: true` if that fallback is unwanted.
 
 - New `skipSymbolIndex` run option: the run builds the file tree but skips the tree-sitter parse of every project file, leaving `fileTokenScores` and `tokenCallers` empty. Set it when your agents do not use the file-picker, `read_subtree` symbols or `read_files`' `referencedBy`.
diff --git a/sdk/src/__tests__/load-agents.test.ts b/sdk/src/__tests__/load-agents.test.ts
index 84fc11645a..eed6053dea 100644
--- a/sdk/src/__tests__/load-agents.test.ts
+++ b/sdk/src/__tests__/load-agents.test.ts
@@ -376,6 +376,63 @@ describe('loadLocalAgents', () => {
       expect(existsSync(markerFile)).toBe(false)
     })
 
+    test('skips plugin hook directories without importing executable scripts', async () => {
+      const vendorHookDir = path.join(agentsDir, 'vendor', 'ponytail', 'hooks')
+      const directHookDir = path.join(agentsDir, 'ponytail', 'hooks')
+      mkdirSync(vendorHookDir, { recursive: true })
+      mkdirSync(directHookDir, { recursive: true })
+      const vendorMarker = path.join(tempDir, 'vendor-hook-side-effect')
+      const directMarker = path.join(tempDir, 'direct-hook-side-effect')
+      const vendorSupportMarker = path.join(
+        tempDir,
+        'vendor-support-side-effect',
+      )
+      writeAgentFile(
+        vendorHookDir,
+        'ponytail-subagent.js',
+        `
+          const { writeFileSync } = require('fs')
+          writeFileSync(${JSON.stringify(vendorMarker)}, 'imported')
+        `,
+      )
+      writeAgentFile(
+        path.join(agentsDir, 'vendor'),
+        'support.js',
+        `
+          const { writeFileSync } = require('fs')
+          writeFileSync(${JSON.stringify(vendorSupportMarker)}, 'imported')
+        `,
+      )
+      writeAgentFile(
+        directHookDir,
+        'subagent.js',
+        `
+          const { writeFileSync } = require('fs')
+          writeFileSync(${JSON.stringify(directMarker)}, 'imported')
+        `,
+      )
+      writeAgentFile(
+        agentsDir,
+        'real-agent.ts',
+        `
+          export default {
+            id: 'real-agent',
+            displayName: 'Real Agent',
+            model: '${MODEL_NAME}'
+          }
+        `,
+      )
+
+      const result: LoadedAgents = await loadLocalAgents({
+        agentsPath: agentsDir,
+      })
+
+      expect(result['real-agent']).toBeDefined()
+      expect(existsSync(vendorMarker)).toBe(false)
+      expect(existsSync(vendorSupportMarker)).toBe(false)
+      expect(existsSync(directMarker)).toBe(false)
+    })
+
     test('converts handleSteps function to string', async () => {
       mkdirSync(agentsDir, { recursive: true })
       writeAgentFile(
@@ -984,6 +1041,10 @@ describe('loadLocalAgents', () => {
       mkdirSync(path.join(agentsDir, 'skills', 'x'), { recursive: true })
       mkdirSync(path.join(agentsDir, 'nested'), { recursive: true })
       mkdirSync(path.join(agentsDir, 'node_modules'), { recursive: true })
+      mkdirSync(path.join(agentsDir, 'vendor', 'ponytail', 'hooks'), {
+        recursive: true,
+      })
+      mkdirSync(path.join(agentsDir, 'ponytail', 'hooks'), { recursive: true })
       writeFileSync(path.join(agentsDir, 'a.ts'), '')
       writeFileSync(path.join(agentsDir, 'b.mjs'), '')
       writeFileSync(path.join(agentsDir, 'nested', 'c.js'), '')
@@ -992,6 +1053,12 @@ describe('loadLocalAgents', () => {
       writeFileSync(path.join(agentsDir, 'README.md'), '')
       writeFileSync(path.join(agentsDir, 'skills', 'x', 'SKILL.md'), '')
       writeFileSync(path.join(agentsDir, 'node_modules', 'dep.js'), '')
+      writeFileSync(
+        path.join(agentsDir, 'vendor', 'ponytail', 'hooks', 'hook.js'),
+        '',
+      )
+      writeFileSync(path.join(agentsDir, 'vendor', 'support.js'), '')
+      writeFileSync(path.join(agentsDir, 'ponytail', 'hooks', 'hook.js'), '')
 
       expect(listLocalAgentFiles(agentsDir).sort()).toEqual([
         path.join(agentsDir, 'a.ts'),
diff --git a/sdk/src/agents/load-agents.ts b/sdk/src/agents/load-agents.ts
index 112f2d1e5c..9a684d38d6 100644
--- a/sdk/src/agents/load-agents.ts
+++ b/sdk/src/agents/load-agents.ts
@@ -112,7 +112,9 @@ const shouldSkipAgentDirectory = (name: string): boolean =>
   name.startsWith('.') ||
   name === 'node_modules' ||
   name === 'scripts' ||
+  name === 'hooks' ||
   name === 'skills' ||
+  name === 'vendor' ||
   name.startsWith('skills-')
 
 const isLoadableAgentFileName = (fileName: string): boolean => {
@@ -127,9 +129,9 @@ const isLoadableAgentFileName = (fileName: string): boolean => {
 /**
  * List every file under `dir` that `loadLocalAgents` would import: `.ts`,
  * `.tsx`, `.js`, `.mjs` or `.cjs`, minus `.d.ts` and test files, skipping
- * `skills/`, `scripts/`, `node_modules` and dot-directories. Hosts use this to
- * decide whether a repository-scoped `.agents` directory contains anything
- * executable before importing it.
+ * `skills/`, `scripts/`, `hooks/`, `vendor/`, `node_modules` and
+ * dot-directories. Hosts use this to decide whether a repository-scoped
+ * `.agents` directory contains anything executable before importing it.
  *
  * @returns Absolute file paths; empty when the directory does not exist.
  */