# MCP SDK v1.26.0 Upgrade Notes
## Summary
Successfully upgraded Chlorpromazine MCP Server from SDK v1.12.0 to v1.26.0 to comply with MCP specification 2025-11-25.
## Changes Made
### 1. SDK Version Update
- **From**: `@modelcontextprotocol/sdk@^1.12.0`
- **To**: `@modelcontextprotocol/sdk@^1.26.0`
- **Added**: `zod@^4.3.6` as direct dependency (SDK uses Zod 4)
### 2. Security Fix
- Addresses **GHSA-345p-7cg4-v4c7**: Cross-client response data leak vulnerability
### 3. Breaking API Changes
#### CallToolResult Schema
**Removed deprecated fields:**
- `toolName` - No longer part of the result schema
- `toolRunId` - No longer part of the result schema
**Updated all tool handlers:**
- `src/tools/sober-thinking/handler.ts`
- `src/tools/kill-trip/handler.ts`
- `src/handlers/tools-handler.ts`
- `server.ts` (root file)
#### Tool Input Parameters
**Changed from `params.input` to `params.arguments`:**
```typescript
// Old (v1.12.0)
const args = validateToolInput(validator, params.input);
// New (v1.26.0)
const args = validateToolInput(validator, params.arguments);
```
#### Server Capabilities
**Removed deprecated capability properties:**
```typescript
// Old (v1.12.0)
capabilities: {
sampling: { createMessage: true },
tools: { list: true, call: true },
prompts: { list: true, get: true }
}
// New (v1.26.0)
capabilities: {
experimental: {},
tools: {},
prompts: {}
}
```
#### Message Content Structure
**Changed from single object to array:**
```typescript
// Old (v1.12.0)
if (lastUserMessage.content.type === 'text') {
const text = lastUserMessage.content.text;
}
// New (v1.26.0)
if (Array.isArray(lastUserMessage.content)) {
const textContent = lastUserMessage.content.find(c => c.type === 'text');
if (textContent && textContent.type === 'text') {
const text = textContent.text;
}
}
```
#### CreateMessage Parameters
**Removed `model` parameter from request:**
- The `params.model` field no longer exists in `CreateMessageRequestSchema`
- Always use `DEFAULT_ASSISTANT_MODEL` in responses
### 4. Tool Definition Enhancements
**Added `title` field:**
```typescript
const soberThinkingTool = {
name: 'sober_thinking',
title: 'Sober Thinking - Reality Check', // NEW
description: '...',
inputSchema: {
type: 'object',
properties: {},
additionalProperties: false // UPDATED per spec
},
outputSchema: { ... }
};
```
## Files Modified
### Core Server Files
- `package.json` - SDK version bump, added Zod 4
- `server.ts` - Updated capabilities, message handling, tool results
- `src/server.ts` - Updated capabilities
### Handler Files
- `src/handlers/message-handler.ts` - Array-based content handling
- `src/handlers/tools-handler.ts` - Removed deprecated fields
### Tool Implementation Files
- `src/tools/sober-thinking/handler.ts` - Updated params.arguments, removed deprecated fields
- `src/tools/kill-trip/handler.ts` - Updated params.arguments, removed deprecated fields
### Documentation
- `README.md` - Updated SDK version reference
- `CHANGELOG.md` - Added v0.4.0 entry
- `UPGRADE_NOTES.md` - This file
## Testing Required
After deployment, verify:
1. **Tools work correctly:**
```bash
# Test sober_thinking tool
# Test kill_trip tool
```
2. **Message handling works:**
```bash
# Test sampling/createMessage with text content
```
3. **Capabilities are properly advertised:**
```bash
# Check initialize response includes tools and prompts capabilities
```
## Next Steps
1. Run `npm install` to update dependencies
2. Run `npm run build` to compile TypeScript
3. Test locally before deploying to Smithery.ai
4. Monitor for any runtime issues after deployment
## References
- [MCP Specification 2025-11-25](https://modelcontextprotocol.io/specification/2025-11-25)
- [MCP SDK v1.26.0 Release](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/v1.26.0)
- [Security Advisory GHSA-345p-7cg4-v4c7](https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7)
