Fix MCP server API migration and improve logging

[justintanner]

Hello!

Amazing project you have here, I like it so much I got Gemini to make some changes so that it runs locally without error (mac).

I sorry this is a "works on my machine" type PR, but I think the fixes Gemini came up with are good.

Changes

1. MCP Server API Migration (src/server/routers/mcp.ts)

The MCP SDK deprecated the .tool() API in favor of .registerTool(). This updates the code to use the new API format:

Before:

this.mcpServer.tool(
  "get-video-status",
  "Get the status of a video...",
  { videoId: z.string().describe("...") },
  async ({ videoId }) => { ... }
);

After:

this.mcpServer.registerTool(
  "get-video-status",
  {
    description: "Get the status of a video...",
    inputSchema: z.object({
      videoId: z.string().describe("..."),
    }) as any,
  },
  async (args: any) => {
    const { videoId } = args;
    // ...
  }
);

Key changes:

• Migrated from .tool(name, description, schema, handler) to .registerTool(name, { description, inputSchema }, handler)
• Updated schema format to use z.object() wrapper for inputSchema
• Added explicit type annotations (as const) for content types
• Removed deprecated capabilities object from McpServer constructor

Impact: Without this change, the MCP server will fail with newer SDK versions.

2. Kokoro ArrayBuffer Fix (src/short-creator/libraries/Kokoro.ts)

Fixed concatWavBuffers() to properly return an ArrayBuffer instead of a Node.js Buffer:

// Before: returned Buffer (wrong type)
return Buffer.concat([header, ...dataParts]);

// After: properly extracts ArrayBuffer from Buffer
const result = Buffer.concat([header, ...dataParts]);
return result.buffer.slice(result.byteOffset, result.byteOffset + result.byteLength);

This ensures type consistency with the function signature and prevents potential issues with downstream ArrayBuffer consumers.

3. FFmpeg Structured Logging (src/short-creator/libraries/FFmpeg.ts)

Updated FFmpeg initialization logging to use Pino's structured format:

// Before: string concatenation
logger.info("FFmpeg path set to:", ffmpegInstaller.path);

// After: structured logging
logger.info({ path: ffmpegInstaller.path }, "FFmpeg path set to");

This improves log parsing and consistency with the rest of the codebase's logging patterns.

Compatibility

• Non-breaking: ArrayBuffer and logging changes are backward compatible