[GitLab] create_or_update_file tool schema broken with zod v4 — zodToJsonSchema returns empty schema (missing "type": "object")

[xieliuduo-ai]

Bug Description

The create_or_update_file tool (and likely all other tools) in @modelcontextprotocol/server-gitlab@2025.4.25 produces an invalid JSON Schema that breaks Claude API and other LLM tool-calling APIs.

The generated inputSchema is:

{
  "$schema": "http://json-schema.org/draft-07/schema#"
}

Missing [type](vscode-file://vscode-app/Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/code/electron-browser/workbench/workbench.html), properties, and required — making it an empty/invalid schema.

Root Cause
The package has "zod-to-json-schema": "^3.23.5" as a dependency, but zod resolves to v4.3.6 (zod v4). zod-to-json-schema@3.x does not support zod v4 — calling [zodToJsonSchema()](vscode-file://vscode-app/Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/code/electron-browser/workbench/workbench.html) on a zod v4 schema silently returns an empty object.

Reproduction


npx -y @modelcontextprotocol/server-gitlab  # installs with zod 4.x

import { zodToJsonSchema } from 'zod-to-json-schema';
import { CreateOrUpdateFileSchema } from './dist/schemas.js';

console.log(JSON.stringify(zodToJsonSchema(CreateOrUpdateFileSchema), null, 2));
// Output: { "$schema": "http://json-schema.org/draft-07/schema#" }
// Expected: { "type": "object", "properties": { ... }, "required": [ ... ] }


Versions
@modelcontextprotocol/server-gitlab: 2025.4.25
zod (resolved): 4.3.6
zod-to-json-schema: 3.25.1
Impact
This completely breaks all tool-calling for any MCP client using this server. For example, Claude API returns:

Since all tools are validated before any request, this blocks every conversation — not just GitLab-related ones.

Suggested Fix
Either:

Pin zod to v3 in [package.json](vscode-file://vscode-app/Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/code/electron-browser/workbench/workbench.html): "zod": "^3.23.0" (quick fix)
Upgrade zod-to-json-schema to v4+ which supports zod v4 (proper fix)
Or add both zod@4 + zod-to-json-schema@4 as a coordinated upgrade
Environment
OS: macOS
Node.js: v22.x
MCP client: VS Code GitHub Copilot

[cliffhall]

Thanks for the report. The server referenced here has been archived and is no longer maintained in this repository, so this bug won't be addressed upstream. Please use a community-maintained fork or an actively-maintained alternative.