Bug: Server fails with "Invalid output schema... draft-07" on all tool calls
Environment
- Package:
@meshy-ai/meshy-mcp-server
- Version: 0.4.0 (latest on npm as of report date)
- OS: macOS
- MCP Clients tested: Claude Desktop (v. current) and Claude Code v2.1.241
- Install method:
npx add-mcp @meshy-ai/meshy-mcp-server --env MESHY_API_KEY=...
Description
After a clean install and valid API key configuration, every tool call (including meshy_check_balance and meshy_text_to_3d) fails with the same error on both Claude Desktop and Claude Code:
واجهت مشكلة تقنية عند محاولة توليد النموذج ثلاثي الأبعاد. أداة Meshy المتصلة بجهازك ترجع خطأ برمجياً ثابتًا:
السبب: خادم Meshy MCP يُعرّف مخطط الإخراج (output schema) بصيغة قديمة (draft-07) غير مدعومة من الأدوات المتوافقة مع الجلسة الحالية.
(Translated summary: The Meshy MCP server defines its output schema using the legacy draft-07 JSON Schema format, which is not supported/validated correctly by the current MCP client tooling. This causes every tool invocation to fail, including simple ones like balance checks.)
Steps to Reproduce
- Install via
npx add-mcp @meshy-ai/meshy-mcp-server --env MESHY_API_KEY=<valid_key>
- Confirm install targets Claude Desktop and/or Claude Code
- Restart the client
- Confirm server status shows connected/running
- Trigger any tool call (e.g., ask Claude to check Meshy credit balance, or generate a 3D model from text)
- Observe failure referencing an outdated
draft-07 output schema definition
Expected Behavior
Tool calls should execute normally and return valid results (balance check, model generation, etc.)
Actual Behavior
All tool calls fail immediately with an output schema validation error referencing the draft-07 JSON Schema draft version.
Additional Notes
- API key was verified correct and valid (confirmed via working config with no
Invalid MESHY_API_KEY errors)
- Server shows as "running"/"connected" in both clients' UI before the schema error surfaces
- Issue is consistent and reproducible across two separate MCP client implementations (Claude Desktop, Claude Code), suggesting the schema definition itself in the package output is the root cause rather than client-side incompatibility
npm cache clean --force + reinstall did not resolve the issue- Confirmed 0.4.0 is the latest published version via
npm view @meshy-ai/meshy-mcp-server version
Suggested Fix
Update the output schema definitions in the server's tool registration to use a JSON Schema draft version compatible with current MCP client validators (e.g., draft 2020-12 or whichever the MCP SDK currently expects).
Bug: Server fails with "Invalid output schema... draft-07" on all tool calls
Environment
@meshy-ai/meshy-mcp-servernpx add-mcp @meshy-ai/meshy-mcp-server --env MESHY_API_KEY=...Description
After a clean install and valid API key configuration, every tool call (including
meshy_check_balanceandmeshy_text_to_3d) fails with the same error on both Claude Desktop and Claude Code:(Translated summary: The Meshy MCP server defines its output schema using the legacy
draft-07JSON Schema format, which is not supported/validated correctly by the current MCP client tooling. This causes every tool invocation to fail, including simple ones like balance checks.)Steps to Reproduce
npx add-mcp @meshy-ai/meshy-mcp-server --env MESHY_API_KEY=<valid_key>draft-07output schema definitionExpected Behavior
Tool calls should execute normally and return valid results (balance check, model generation, etc.)
Actual Behavior
All tool calls fail immediately with an output schema validation error referencing the
draft-07JSON Schema draft version.Additional Notes
Invalid MESHY_API_KEYerrors)npm cache clean --force+ reinstall did not resolve the issuenpm view @meshy-ai/meshy-mcp-server versionSuggested Fix
Update the output schema definitions in the server's tool registration to use a JSON Schema draft version compatible with current MCP client validators (e.g., draft 2020-12 or whichever the MCP SDK currently expects).