MCP server startup error: Invalid schema for tool initialize_project (JSON Schema Draft 2020-12 not supported)

[almai]

Bug Description

The Taskmaster AI MCP server fails to start in Augment IDE (WebStorm) with the following error:

⚠️  MCP server startup error: Invalid schema for tool initialize_project: no schema with key or ref "https://json-schema.org/draft/2020-12/schema" 
   Command: npx -y --package=task-master-ai task-master-ai

Environment

• Task Master version: 0.28.0 (latest)
• MCP Client: Augment IDE (WebStorm 2025.2)
• Node.js: v22.20.0
• OS: macOS (darwin)

Root Cause

The initialize_project tool is using JSON Schema Draft 2020-12 (https://json-schema.org/draft/2020-12/schema), but the MCP client only supports older JSON Schema drafts (likely Draft-07 or Draft-04).

Impact

• ❌ MCP server fails to start in Augment IDE
• ❌ All Taskmaster AI MCP tools unavailable
• ✅ CLI works fine (task-master command)

Expected Behavior

The MCP server should use a JSON Schema draft version that's compatible with common MCP clients (Draft-07 or Draft-04).

Actual Behavior

MCP server fails to initialize due to unsupported JSON Schema version.

Workaround

None currently available. Users must use the CLI instead of MCP integration.

Suggested Fix

Downgrade the JSON Schema version used in the initialize_project tool definition from Draft 2020-12 to Draft-07 or Draft-04.

Related Information

• MCP Specification: https://modelcontextprotocol.io/
• JSON Schema Draft-07: https://json-schema.org/draft-07/schema
• JSON Schema Draft 2020-12: https://json-schema.org/draft/2020-12/schema

Additional Context

This issue was discovered when trying to use Taskmaster AI MCP server with Augment IDE. The CLI works perfectly, but the MCP integration fails immediately on startup.

The error appears in the Augment IDE output when trying to connect to the MCP server configured in ~/.augment/settings.json.

[Crunchyman-ralph]

Can you maybe try to remove --package=task-master-ai ?

[Crunchyman-ralph]

If that doesn't fix it, I'll have to look into what the issue is and try it on augment code myself

[Crunchyman-ralph]

We are using ai sdk v5 and zod v4 but I doubt that could be an issue.

Either we count on augment code to upgrade to a json schema parser that can parse the latest draft or I'll have to find a workaround if this issue persists

[almai]

I've tried that also. See screenshot. Can I provide you with more information like logs, or so?

[almai]

I'd say the zod version bump in tm v0.28.0 is a strong contender. v4 has a lot of breaking changes.

package.json

[almai]

Downgrading to v0.27.3 worked for me.

[Crunchyman-ralph]

yes, we had to move to zod v4 so that we can upgrade to ai sdk v5

[Crunchyman-ralph]

oh great, that was what I was going to ask you to do

[Crunchyman-ralph]

seems to be a common issue with the mcp sdk, so we multiple options, specifically augment code needs to upgrade their mcp client to a higher version.

There's a PR for this right now:
modelcontextprotocol/typescript-sdk#869

[Crunchyman-ralph]

@claude give it your best shot at solving this