# WASM Implementation Polish Improvements

## Summary
Implemented all suggested polish improvements to enhance the WASM/WASI implementation based on the review feedback.

## Improvements Completed

### 1. ✅ Tool Result Content Format
**Before:** All tool outputs returned as stringified JSON in `Content::Text`
**After:** Smart content detection:
- Plain strings return as direct text
- Objects return as pretty-printed JSON for readability
- Preserves structure for client-side parsing

```rust
let content = if let Some(text) = result_value.as_str() {
    vec![Content::Text { text: text.to_string() }]
} else if result_value.is_object() {
    vec![Content::Text {
        text: serde_json::to_string_pretty(&result_value)
            .unwrap_or_else(|_| "{}".to_string()),
    }]
}
```

### 2. ✅ Error Code Mapping
**Before:** All errors mapped to `INTERNAL_ERROR`
**After:** Protocol errors preserve their specific codes:
- `Protocol` errors retain original error codes
- Graceful fallback to `INTERNAL_ERROR` for other types

```rust
fn map_error_code(error: &Error) -> ErrorCode {
    match error {
        Error::Protocol { code, .. } => *code,
        _ => ErrorCode::INTERNAL_ERROR,
    }
}
```

### 3. ✅ Resource Pagination
**Before:** Simple aggregation with no cursor support
**After:** Smart cursor handling with provider namespacing:
- Cursor format: `"provider:cursor"` for multi-provider pagination
- Sequential provider querying for proper pagination
- Maintains cursor state across requests

```rust
// Parse cursor to determine which provider to query
let (provider_name, provider_cursor) = if let Some(cursor) = params.cursor {
    if let Some((name, cur)) = cursor.split_once(':') {
        (Some(name.to_string()), Some(cur.to_string()))
    } else {
        (None, Some(cursor))
    }
}
```

### 4. ✅ Protocol Version Negotiation
**Before:** Echo client version without validation
**After:** Proper negotiation with fallback:
- Validates client version against `SUPPORTED_PROTOCOL_VERSIONS`
- Falls back to latest supported version if unknown
- Documents behavior in response

```rust
let negotiated_version = if SUPPORTED_PROTOCOL_VERSIONS.contains(&client_version.as_str()) {
    client_version
} else {
    SUPPORTED_PROTOCOL_VERSIONS[0].to_string()
};
```

### 5. ✅ Cloudflare Example Makefile
**Created:** Complete build automation with targets:
- `build` - Build standalone Worker
- `build-sdk` - Build SDK-backed variant
- `deploy` - Deploy to Cloudflare
- `test` - Test deployed worker
- `clean` - Clean artifacts

Key feature: Clear separation between SDK and non-SDK variants with instructions.

### 6. ✅ Unit Tests for WasmMcpServer
**Added:** Comprehensive test suite covering:
- Initialize with supported/unsupported versions
- List tools functionality
- Call existing/nonexistent tools
- Invalid parameter handling
- Error code mapping
- Resource pagination
- Content format variations

Located in: `src/server/wasm_server_tests.rs`

## Test Coverage

| Test Case | Status | Purpose |
|-----------|--------|---------|
| Protocol negotiation | ✅ | Validates version handling |
| Tool discovery | ✅ | Ensures tools are listed correctly |
| Tool execution | ✅ | Tests successful tool calls |
| Error handling | ✅ | Validates error responses |
| Pagination | ✅ | Tests cursor-based resource listing |
| Content formats | ✅ | Validates different response types |

## Impact

These improvements provide:

1. **Better Alignment with TypeScript SDK**: Content format and error handling now match TS SDK patterns
2. **Production Readiness**: Proper error codes, pagination, and version negotiation
3. **Developer Experience**: Makefile automation and comprehensive tests
4. **Maintainability**: Test coverage prevents regressions

## Files Modified

- `src/server/wasm_server.rs` - Core improvements
- `src/server/wasm_server_tests.rs` - Test suite (new)
- `src/server/mod.rs` - Test module registration
- `examples/cloudflare-worker-rust/Makefile` - Build automation (new)

## Next Steps

While not blocking, consider:
1. Adding integration tests with actual WASI runtimes
2. Performance benchmarking across platforms
3. Streaming support investigation for large responses
4. Additional content types beyond Text (Image, Resource, etc.)

## Conclusion

All suggested polish improvements have been successfully implemented, enhancing the robustness and production-readiness of the WASM/WASI implementation while maintaining the clean architecture and environment independence achieved in the main refactoring.