The Model Context Protocol (MCP) Standard
The Model Context Protocol (MCP) standardizes how AI applications connect to external tools, data repositories, and execution environments. By decoupling tool implementation from model execution, MCP servers provide universal composability.
Actionable Error Surfaces
A frequent anti-pattern in tool design is returning generic HTTP 500 error strings or raising uncaught exceptions in the host runtime. When a tool fails, Claude needs structured, actionable error feedback to diagnose and self-correct:
{
"isError": true,
"content": [
{
"type": "text",
"text": "Query failed: Column 'department_code' does not exist on table 'employees'. Available columns: ['id', 'name', 'dept_id', 'salary']."
}
]
}Providing schema metadata in the error message enables Claude to immediately correct its parameters in the next turn without human intervention.