[BUG] Claude Code no longer passing parameters to MCP

Resolved 💬 14 comments Opened Jun 14, 2025 by mattmaslin Closed Jan 8, 2026

Environment

  • Platform (select one):
  • [ X] Anthropic API
  • [ ] AWS Bedrock
  • [ ] Google Vertex AI
  • [ ] Other: <!-- specify -->
  • Claude CLI version: 1.0.24
  • Operating System: EndeavourOS
  • Terminal: Alacritty

Bug Description

Claude code is not able to call an MCP tool that has always worked in the past. I have an MCP task manager that has been build along with a tool to track tasks. It's no longer able to pass a body and update the task properly:

can you also mark 366 as done

⎿  Error: MCP error -32602: failed to deserialize parameters: missing field task_id

● I keep making the same mistake. Let me include the parameters properly:
⎿  Error: MCP error -32602: failed to deserialize parameters: missing field task_id

● I'm not including the body parameters. Let me do this correctly:
⎿  Error: MCP error -32602: failed to deserialize parameters: missing field task_id
⎿  API Error: Request was aborted.

can you check the tool definition and the required body and try again?

● Let me check the tool definition for update_task:

Looking at the function definition from earlier, mcp__memory-bank-mcp__update_task requires:

  • task_id (required, integer)
  • status (optional, string)

Let me call it with the proper parameters:
⎿  Error: MCP error -32602: failed to deserialize parameters: missing field task_id

● I'm still not passing the parameters correctly. Looking at how I successfully called it before for task 362, I need to use <parameter> tags:
⎿  Error: MCP error -32602: failed to deserialize parameters: missing field task_id

● Let me try again with the correct format based on my successful call earlier:
⎿  Error: MCP error -32602: failed to deserialize parameters: missing field task_id
⎿  API Error: Request was aborted.

Additional Context

There have been no updates to this MCP server. Other tools for the MCP server are working properly and parameters are being passed. I have cleared project history and context history and it continues to fail.

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