# Verification Note: bf-1pky5 - Create JSON-RPC response struct

## Summary

The `JsonRpcResponse<T>` generic struct already exists in `crates/pdftract-core/tests/TH-05-ssrf-block.rs` (lines 627-637) and meets all acceptance criteria.

## Acceptance Criteria - ALL PASS ✓

### 1. JsonRpcResponse<T> struct exists with all required fields ✓
**Location:** `crates/pdftract-core/tests/TH-05-ssrf-block.rs:628-637`

```rust
#[derive(Debug, Clone, serde::Deserialize)]
pub struct JsonRpcResponse<T> {
    pub jsonrpc: String,           // ✓ jsonrpc field (expected value: "2.0")
    pub result: Option<T>,        // ✓ result field for successful responses
    pub error: Option<JsonRpcError>, // ✓ error field for error responses
    pub id: ResponseId,            // ✓ id field (more complete than Option)
}
```

### 2. Struct derives Deserialize and is generic over T ✓
- Derives: `Debug, Clone, serde::Deserialize` ✓
- Generic over type parameter `T` ✓

### 3. Fields are public ✓
All fields use `pub` keyword, providing direct access.

### 4. Compiles without errors ✓
Verified with: `cargo check --features remote --tests`
Result: Exit code 0 (success)

## Implementation Notes

The implementation **exceeds** the basic requirements:

1. **ID field uses ResponseId enum** instead of `Option<String>` or `Option<u64>`
   - `ResponseId` is an enum that handles all JSON-RPC 2.0 identifier types:
     - Number(i64)
     - String(String)
     - Null (for notifications)
   - This is more correct per the JSON-RPC 2.0 specification

2. **JsonRpcError struct** also exists (lines 592-599):
   ```rust
   pub struct JsonRpcError {
       pub code: i64,
       pub message: String,
       pub data: Option<serde_json::Value>,
   }
   ```

3. **Helper methods provided** (lines 639-658):
   - `is_success()` - checks if response has result field
   - `is_error()` - checks if response has error field
   - `get_error()` - returns Option<&JsonRpcError>
   - `get_result()` - returns Option<&T>

## Test Coverage

The mcp_helpers module includes comprehensive tests:
- `test_is_ssrf_blocked_error_with_code_in_data` (lines 1069-1083)
- `test_parse_response_success` (lines 1163-1173)
- `test_parse_response_error` (lines 1176-1190)
- Multiple other tests validating the struct's functionality

## Files Modified

**None required** - the struct already exists and compiles successfully.

## Conclusion

The JSON-RPC response struct foundation is complete and ready for use in SSRF blocking tests. The implementation is production-ready and follows the JSON-RPC 2.0 specification correctly.