MCP tool schema optional fields become required in OpenCode (jira_add_comment) #20661

"inputSchema": {
  "required": ["issue_key", "body"],
  "properties": {
    "visibility": { "type": "string", "default": null },
    "public": { "type": "boolean", "default": null }
  }
}

Evidence: OpenCode behavior
In OpenCode session data, actual tool calls include optional params even when not requested:
{
  "tool": "jira_jira_add_comment",
  "input": {
    "issue_key": "xxx",
    "body": "Test",
    "visibility": "",
    "public": false
  }
}
This leads to validation error from MCP Jira:
visibility must be a valid JSON object ...

Suspected root cause
OpenCode MCP tool adapter / tool registry path likely mutates or ignores optional/nullability in incoming inputSchema, causing optional fields to be treated as required (or aggressively auto-filled).

### Plugins

/sooperset/mcp-atlassian

### OpenCode version

1.3.13

### Steps to reproduce

1. Configure remote MCP Jira.
2. Ask model:  write comment "Test" for task xxx
3. Observe tool call args include visibility/public despite not being requested.
4. Observe comment-add failure until fallback/workaround is used.

### Screenshot and/or share link

<img width="1032" height="240" alt="Image" src="https://github.com/user-attachments/assets/65b4a771-6c6b-48b2-820c-746eef5aa8a5" />

### Operating System

Windows 11

### Terminal

_No response_