bug: Q CLI @<prompt> error messages are hard to understand.

[jbshu4546]

Checks

• I have searched github.com/aws/amazon-q-developer-cli/issues and there are no duplicates of my issue

Operating system

MacOS

Expected behaviour

Q CLI tells me exactly what went wrong with my @<prompt> invocation when I omit/malform prompt inputs.

Actual behaviour

Q CLI gives me a raw error message when I omit/malform prompt inputs.

Error encountered while retrieving prompt:
{
  "code": -32602,
  "message": "MCP error -32602: Invalid arguments for prompt {prompt_name}: [\n  {\n    \"{input1}\": \"invalid_type\",\n    \"expected\": \"object\",\n    \"received\": \"undefined\",\n    \"{input2}\": [],\n    \"message\": \"Required\"\n  }\n]"
}

Steps to reproduce

Use @<prompt> and omit inputs.

[jbshu4546]

If the maintainers agree this is an issue, I can take it up myself.

[jbshu4546]

Example of nicely formatted output:

Error encountered while retrieving prompt:
MCP error -32602: Invalid arguments for prompt agent_script_coco_was_sev2_ticket_link_retrieval:
[
  {
    "code": "invalid_type",
    "expected": "string",
    "message": "Required",
    "path": [
      "{input1}"
    ],
    "received": "undefined"
  },
  {
    "code": "invalid_type",
    "expected": "string",
    "message": "Required",
    "path": [
      "{input2}"
    ],
    "received": "undefined"
  },
  {
    "code": "invalid_type",
    "expected": "string",
    "message": "Required",
    "path": [
      "{input3}"
    ],
    "received": "undefined"
  }
]

[jlhood]

This should be fixed by #2953. Should be able to close this now.