Add MCP stdio bridge and database discovery tools

doc/ANOMALY_DETECTION/README.md

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+# Anomaly Detection - Security Threat Detection for ProxySQL
+
+## Overview
+
+The Anomaly Detection module provides real-time security threat detection for ProxySQL using a multi-stage analysis pipeline. It identifies SQL injection attacks, unusual query patterns, rate limiting violations, and statistical anomalies.
+
+## Features
+
+- **Multi-Stage Detection Pipeline**: 5-layer analysis for comprehensive threat detection
+- **SQL Injection Pattern Detection**: Regex-based and keyword-based detection
+- **Query Normalization**: Advanced normalization for pattern matching
+- **Rate Limiting**: Per-user and per-host query rate tracking
+- **Statistical Anomaly Detection**: Z-score based outlier detection
+- **Configurable Blocking**: Auto-block or log-only modes
+- **Prometheus Metrics**: Native monitoring integration
+
+## Quick Start
+
+### 1. Enable Anomaly Detection
+
+```sql
+-- Via admin interface
+SET genai-anomaly_enabled='true';
+```
+
+### 2. Configure Detection
+
+```sql
+-- Set risk threshold (0-100)
+SET genai-anomaly_risk_threshold='70';
+
+-- Set rate limit (queries per minute)
+SET genai-anomaly_rate_limit='100';
+
+-- Enable auto-blocking
+SET genai-anomaly_auto_block='true';
+
+-- Or enable log-only mode
+SET genai-anomaly_log_only='false';
+```
+
+### 3. Monitor Detection Results
+
+```sql
+-- Check statistics
+SHOW STATUS LIKE 'ai_detected_anomalies';
+SHOW STATUS LIKE 'ai_blocked_queries';
+
+-- View Prometheus metrics
+curl http://localhost:4200/metrics | grep proxysql_ai
+```
+
+## Configuration
+
+### Variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `genai-anomaly_enabled` | true | Enable/disable anomaly detection |
+| `genai-anomaly_risk_threshold` | 70 | Risk score threshold (0-100) for blocking |
+| `genai-anomaly_rate_limit` | 100 | Max queries per minute per user/host |
+| `genai-anomaly_similarity_threshold` | 85 | Similarity threshold for embedding matching (0-100) |
+| `genai-anomaly_auto_block` | true | Automatically block suspicious queries |
+| `genai-anomaly_log_only` | false | Log anomalies without blocking |
+
+### Status Variables
+
+| Variable | Description |
+|----------|-------------|
+| `ai_detected_anomalies` | Total number of anomalies detected |
+| `ai_blocked_queries` | Total number of queries blocked |
+
+## Detection Methods
+
+### 1. SQL Injection Pattern Detection
+
+Detects common SQL injection patterns using regex and keyword matching:
+
+**Patterns Detected:**
+- OR/AND tautologies: `OR 1=1`, `AND 1=1`
+- Quote sequences: `'' OR ''=''`
+- UNION SELECT: `UNION SELECT`
+- DROP TABLE: `DROP TABLE`
+- Comment injection: `--`, `/* */`
+- Hex encoding: `0x414243`
+- CONCAT attacks: `CONCAT(0x41, 0x42)`
+- File operations: `INTO OUTFILE`, `LOAD_FILE`
+- Timing attacks: `SLEEP()`, `BENCHMARK()`
+
+**Example:**
+```sql
+-- This query will be blocked:
+SELECT * FROM users WHERE username='admin' OR 1=1--' AND password='xxx'
+```
+
+### 2. Query Normalization
+
+Normalizes queries for consistent pattern matching:
+- Case normalization
+- Comment removal
+- Literal replacement
+- Whitespace normalization
+
+**Example:**
+```sql
+-- Input:
+SELECT * FROM users WHERE name='John' -- comment
+
+-- Normalized:
+select * from users where name=?
+```
+
+### 3. Rate Limiting
+
+Tracks query rates per user and host:
+- Time window: 1 hour
+- Tracks: Query count, last query time
+- Action: Block when limit exceeded
+
+**Configuration:**
+```sql
+SET ai_anomaly_rate_limit='100';
+```
+
+### 4. Statistical Anomaly Detection
+
+Uses Z-score analysis to detect outliers:
+- Query execution time
+- Result set size
+- Query frequency
+- Schema access patterns
+
+**Example:**
+```sql
+-- Unusually large result set:
+SELECT * FROM huge_table -- May trigger statistical anomaly
+```
+
+### 5. Embedding-based Similarity
+
+(Framework for future implementation)
+Detects similarity to known threat patterns using vector embeddings.
+
+## Examples
+
+### SQL Injection Detection
+
+```sql
+-- Blocked: OR 1=1 tautology
+mysql> SELECT * FROM users WHERE username='admin' OR 1=1--';
+ERROR 1313 (HY000): Query blocked: SQL injection pattern detected
+
+-- Blocked: UNION SELECT
+mysql> SELECT name FROM products WHERE id=1 UNION SELECT password FROM users;
+ERROR 1313 (HY000): Query blocked: SQL injection pattern detected
+
+-- Blocked: Comment injection
+mysql> SELECT * FROM users WHERE id=1-- AND password='xxx';
+ERROR 1313 (HY000): Query blocked: SQL injection pattern detected
+```
+
+### Rate Limiting
+
+```sql
+-- Set low rate limit for testing
+SET ai_anomaly_rate_limit='10';
+
+-- After 10 queries in 1 minute:
+mysql> SELECT 1;
+ERROR 1313 (HY000): Query blocked: Rate limit exceeded for user 'app_user'
+```
+
+### Statistical Anomaly
+
+```sql
+-- Unusual query pattern detected
+mysql> SELECT * FROM users CROSS JOIN orders CROSS JOIN products;
+-- May trigger: Statistical anomaly detected (high result count)
+```
+
+## Log-Only Mode
+
+For monitoring without blocking:
+
+```sql
+-- Enable log-only mode
+SET ai_anomaly_log_only='true';
+SET ai_anomaly_auto_block='false';
+
+-- Queries will be logged but not blocked
+-- Monitor via:
+SHOW STATUS LIKE 'ai_detected_anomalies';
+```
+
+## Monitoring
+
+### Prometheus Metrics
+
+```bash
+# View AI metrics
+curl http://localhost:4200/metrics | grep proxysql_ai
+
+# Output includes:
+# proxysql_ai_detected_anomalies_total
+# proxysql_ai_blocked_queries_total
+```
+
+### Admin Interface
+
+```sql
+-- Check detection statistics
+SELECT * FROM stats_mysql_global WHERE variable_name LIKE 'ai_%';
+
+-- View current configuration
+SELECT * FROM runtime_mysql_servers WHERE variable_name LIKE 'ai_anomaly_%';
+```
+
+## Troubleshooting
+
+### Queries Being Blocked Incorrectly
+
+1. **Check if legitimate queries match patterns**:
+   - Review the SQL injection patterns list
+   - Consider log-only mode for testing
+
+2. **Adjust risk threshold**:
+   ```sql
+   SET ai_anomaly_risk_threshold='80';  -- Higher threshold
+   ```
+
+3. **Adjust rate limit**:
+   ```sql
+   SET ai_anomaly_rate_limit='200';  -- Higher limit
+   ```
+
+### False Positives
+
+If legitimate queries are being flagged:
+
+1. Enable log-only mode to investigate:
+   ```sql
+   SET ai_anomaly_log_only='true';
+   SET ai_anomaly_auto_block='false';
+   ```
+
+2. Check logs for specific patterns:
+   ```bash
+   tail -f proxysql.log | grep "Anomaly:"
+   ```
+
+3. Adjust configuration based on findings
+
+### No Anomalies Detected
+
+If detection seems inactive:
+
+1. Verify anomaly detection is enabled:
+   ```sql
+   SELECT * FROM runtime_mysql_servers WHERE variable_name='ai_anomaly_enabled';
+   ```
+
+2. Check logs for errors:
+   ```bash
+   tail -f proxysql.log | grep "Anomaly:"
+   ```
+
+3. Verify AI features are initialized:
+   ```bash
+   grep "AI_Features" proxysql.log
+   ```
+
+## Security Considerations
+
+1. **Anomaly Detection is a Defense in Depth**: It complements, not replaces, proper security practices
+2. **Pattern Evasion Possible**: Attackers may evolve techniques; regular updates needed
+3. **Performance Impact**: Detection adds minimal overhead (~1-2ms per query)
+4. **Log Monitoring**: Regular review of anomaly logs recommended
+5. **Tune for Your Workload**: Adjust thresholds based on your query patterns
+
+## Performance
+
+- **Detection Overhead**: ~1-2ms per query
+- **Memory Usage**: ~100KB for user statistics
+- **CPU Usage**: Minimal (regex-based detection)
+
+## API Reference
+
+See `API.md` for complete API documentation.
+
+## Architecture
+
+See `ARCHITECTURE.md` for detailed architecture information.
+
+## Testing
+
+See `TESTING.md` for testing guide and examples.