db-mcp (SQLite MCP Server)

SQLite MCP Server with 170+ specialized tools, 11 data resources + 11 help resources, and 10 prompts, audit logging with DDL backup snapshots, HTTP/SSE Transport, OAuth 2.1 authentication, tool filtering, granular access control, and structured error handling with categorized, actionable responses. Available in WASM and better-sqlite3 variants.

Wiki • Changelog

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🎯 What Sets Us Apart

Feature	Description
181+ Specialized Tools	The most comprehensive SQLite MCP server available — core CRUD, JSON/JSONB, FTS5 full-text search, statistical analysis, vector search, geospatial/SpatiaLite, introspection, migration, and admin
Deep Observability	Built-in Prometheus /metrics export, real-time sqlite://metrics MCP resource, historical persistence to a SystemDb sidecar, and a granular sqlite_audit_search tool for compliance and investigation
Dynamic Configuration	Full YAML/JSON config file support (--config) with precedence rules, plus a sqlite_server_config tool for live runtime config updates (e.g., log levels) without server restarts
Advanced Query & Search	O(1) cursor-based keyset pagination, faceted search aggregation, and sqlite_hybrid_search orchestrating FTS5 + Vector similarity with Reciprocal Rank Fusion (RRF) in a single tool call
AI Index Recommendations	sqlite_index_audit automatically analyzes EXPLAIN QUERY PLAN responses to suggest optimized composite and partial indexes based on workload patterns
Real-time Subscriptions	Native resources/subscribe support pushing event-driven notifications for sqlite://schema DDL changes and periodic sqlite://health updates directly to clients
22 Resources	11 data resources (schema, tables, table_schema, indexes, views, health, meta, audit, metrics, compile_options, pragma) + 11 help resources (sqlite://help + per-group reference) — filtered by --tool-filter
10 AI-Powered Prompts	Guided workflows for schema exploration, query building, data analysis, optimization, migration, debugging, and hybrid FTS5 + vector search
Code Mode	Massive Token Savings: Execute complex, multi-step operations inside a V8 isolate sandbox with process-level isolation and hard timeouts. Instead of spending thousands of tokens on back-and-forth tool calls, Code Mode exposes all 180+ capabilities locally, reducing token overhead by 70–90% and supercharging AI agent reasoning
Token-Optimized Payloads	Every tool response is designed for minimal token footprint with _meta.tokenEstimate on every response so agents know their token cost. Tools include compact, nodesOnly, maxOutliers, minSeverity, and maxInvalid parameters where applicable — letting agents control response size without losing data access
Dual SQLite Backends	WASM (sql.js) for zero-compilation portability, Native (better-sqlite3) for high-performance concurrent execution with full features including transactions, window functions, and SpatiaLite GIS
OAuth 2.1 + Access Control	Enterprise-ready security with RFC 9728/8414 compliance, granular scopes (full, read, write, admin, db:*, table:*:*), and Keycloak integration
Smart Tool Filtering	10 tool groups + 7 shortcuts let you stay within IDE limits while exposing exactly what you need
HTTP Streaming Transport	Streamable HTTP (/mcp) for modern clients + legacy SSE (/sse) for backward compatibility — both protocols supported simultaneously with security headers, rate limiting, health check, and stateless mode for serverless
Production-Ready Security	SQL injection protection (parameterized queries + Unicode-normalized WHERE clause validation), sandboxed code execution (V8 codeGeneration restrictions, frozen prototypes, 29 blocked patterns, Proxy nullified, RPC allowlist), CORS deny-all default, fail-closed scope enforcement, JWT claims sanitization, 7 security headers, body size limits, rate limiting with Retry-After, slowloris timeouts, trustedProxyIps, opt-in HSTS, non-root Docker, and build provenance
Encryption at Rest	Native SQLCipher support via --encryption-key or DB_ENCRYPTION_KEY. Dynamically loads better-sqlite3-multiple-ciphers and automatically encrypts the sidecar SystemDb audit logs to prevent sensitive queries from leaking
Strict TypeScript	100% type-safe codebase with strict mode, no any types, 1911 unit tests + 1136 E2E tests and 90% coverage
Deterministic Error Handling	Every tool returns structured {success, error, code, category, suggestion, recoverable} responses — no raw exceptions, no silent failures. Agents get enriched error context with actionable suggestions instead of cryptic SQLite codes
MCP 2025-03-26 Compliant	Full protocol support with tool safety hints (sensitiveHint, readOnlyHint), resource priorities, and progress notifications

🚀 Quick Start

Option 1: Docker (Recommended)

Pull and run instantly:

docker pull writenotenow/db-mcp:latest

Run with volume mount:

docker run -i --rm \
  -v $(pwd):/workspace \
  writenotenow/db-mcp:latest \
  --sqlite-native /workspace/database.db

Option 2: Node.js Installation

Clone the repository:

git clone https://github.com/neverinfamous/db-mcp.git

Navigate to directory:

cd db-mcp

Install dependencies:

pnpm install

Build the project:

pnpm run build

Run the server with Native backend (better-sqlite3 — full features, requires Node.js native build):

node dist/cli.js --transport stdio --sqlite-native ./database.db

Or with WASM backend (sql.js — cross-platform, no compilation required):

node dist/cli.js --transport stdio --sqlite ./database.db

Backend Choice: Use --sqlite-native for full features (181 MCP tools / 170 group tools, transactions, window functions, SpatiaLite). Use --sqlite for WASM mode (154 MCP tools / 143 group tools, no native dependencies).

Verify It Works

node dist/cli.js --transport stdio --sqlite-native :memory:

Expected output:

[db-mcp] Starting MCP server...
[db-mcp] Registered adapter: Native SQLite Adapter (better-sqlite3) (sqlite:default)
[db-mcp] Server started successfully

Run the test suite:

pnpm run test

Prerequisites

• ✅ Docker installed and running (for Docker method)
• ✅ Node.js 24+ (LTS) (for local installation)

Code Mode: Maximum Efficiency

Code Mode (sqlite_execute_code) dramatically reduces token usage (70–90%) and is included by default in all presets.

Code executes in a worker-thread sandbox — a separate V8 isolate with its own memory space. All sqlite.* API calls are forwarded to the main thread via a MessagePort-based RPC bridge, where the actual database operations execute. This provides:

• Process-level isolation — user code runs in a separate V8 instance with enforced heap limits
• Readonly enforcement — when readonly: true, stripped methods throw clear error messages listing available methods via Proxy traps
• Hard timeouts — worker termination if execution exceeds the configured limit
• V8 code generation restrictions — eval() and Function() construction from strings disabled at the V8 engine level via codeGeneration: { strings: false, wasm: false }
• RPC allowlist — host-side validation prevents workers from invoking unauthorized API methods
• Full API access — all 10 tool groups are available via sqlite.* (e.g., sqlite.core.readQuery(), sqlite.json.extract())

Set CODEMODE_ISOLATION=vm with CODEMODE_ISOLATION_INSECURE=1 to fall back to the in-process vm module sandbox if needed.

⚡ Code Mode Only (Maximum Token Savings)

If you control your own setup, you can run with only Code Mode enabled — a single tool that provides access to all 180+ tools' worth of capability through the sqlite.* API:

{
  "mcpServers": {
    "db-mcp-sqlite": {
      "command": "node",
      "args": [
        "/path/to/db-mcp/dist/cli.js",
        "--transport",
        "stdio",
        "--sqlite-native",
        "/path/to/database.db",
        "--tool-filter",
        "codemode"
      ]
    }
  }
}

This exposes just sqlite_execute_code plus built-in tools. The agent writes JavaScript against the typed sqlite.* SDK — composing queries, chaining operations across all 10 tool groups, and returning exactly the data it needs — in one execution. This mirrors the Code Mode pattern pioneered by Cloudflare for their entire API: fixed token cost regardless of how many capabilities exist.

[!TIP] Maximize Token Savings: Instruct your AI agent to prefer Code Mode over individual tool calls:

"When using db-mcp, prefer sqlite_execute_code (Code Mode) for multi-step database operations to minimize token usage."

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🎛️ Tool Filtering

[!IMPORTANT] AI-enabled IDEs like Cursor have tool limits. With 180+ tools in the native backend, you must use tool filtering to stay within limits. Use shortcuts or specify groups to enable only what you need.

Quick Start: Recommended Configurations

Starter (core + json + text)

If you prefer individual tool calls, starter provides Core + JSON + Text:

{
  "args": ["--tool-filter", "starter"]
}

Custom Groups

Specify exactly the groups you need:

{
  "args": ["--tool-filter", "core,json,stats"]
}

Shortcuts (Predefined Bundles)

Note: Native includes FTS5 (5), window functions (6), transactions (8), and SpatiaLite (7) not available in WASM.

Shortcut	WASM	Native	+ Built-in	What's Included
starter	65	70	+4	Core, JSON, Text
analytics	67	73	+4	Core, JSON, Stats
search	51	56	+4	Core, Text, Vector
spatial	40	47	+4	Core, Geo, Vector
dev-schema	41	41	+4	Core, Introspection, Migration
minimal	25	25	+4	Core only
full	143	170	+4	Everything enabled

Tool Groups (10 Available)

Note: +4 built-in tools (server_info, server_health, list_adapters, sqlite_execute_code) are injected into every group.

Group	WASM	Native	+ Built-in	Description
core	25	25	+4	Basic CRUD, schema, tables
json	25	25	+4	JSON/JSONB operations, analysis
text	15	20	+4	Text processing + FTS5 + advanced search
stats	17	23	+4	Descriptive, inference, window functions
vector	11	11	+4	Vector storage, similarity search
admin	30	31	+4	DB maintenance, backup, virtual tables
transactions	0	8	+4	Commit, rollback, savepoints (Native only)
geo	4	11	+4	Geospatial + SpatiaLite (Native only)
introspection	10	10	+4	Schema mapping, FK graph, analysis
migration	6	6	+4	Schema migration tracking (opt-in)

Syntax Reference

Prefix	Target	Example	Effect
(none)	Shortcut	starter	Whitelist Mode: Enable ONLY this shortcut
(none)	Group	core	Whitelist Mode: Enable ONLY this group
(none)	Tool	read_query	Whitelist Mode: Enable ONLY this tool
+	Group	+vector	Add tools from this group to current set
-	Group	-admin	Remove tools in this group from current set
+	Tool	+fuzzy_search	Add one specific tool
-	Tool	-drop_table	Remove one specific tool

Custom Tool Selection

You can list individual tool names (without + prefix) to create a fully custom whitelist — only the tools you specify will be enabled:

Enable exactly 3 tools (whitelist mode):

--tool-filter "read_query,write_query,list_tables"

Mix tools from different groups:

--tool-filter "read_query,fuzzy_search,vector_search"

Combine with a shortcut or group:

--tool-filter "starter,+vector_search,+fuzzy_search"

This is useful for scripted or automated clients that need a minimal, precise set of capabilities.

Examples:

--tool-filter "starter"
--tool-filter "core,json,text,stats"
--tool-filter "starter,+stats"
--tool-filter "starter,-vector"

Legacy Syntax (still supported): If you start with a negative filter (e.g., -vector,-geo), it assumes you want to start with all tools enabled and then subtract.

--tool-filter "-stats,-vector,-geo,-backup,-monitoring,-transactions,-window"

🔌 SQLite Extensions

SQLite supports both built-in extensions (compiled into better-sqlite3) and loadable extensions (require separate binaries).

Built-in Extensions (work out of box)

Extension	Purpose	Status
FTS5	Full-text search with BM25 ranking	✅ Always loaded
JSON1	JSON functions (json_extract, etc.)	✅ Always loaded
R-Tree	Spatial indexing for bounding boxes	✅ Always loaded

Loadable Extensions (require installation)

Extension	Purpose	Tools	CLI Flag
CSV	CSV virtual tables	2	--csv
SpatiaLite	Advanced GIS capabilities	7	--spatialite

Installing Extensions

CSV Extension:

Download a precompiled binary or compile from source: https://www.sqlite.org/csv.html

Set the environment variable (Linux/macOS):

export CSV_EXTENSION_PATH=/path/to/csv.so

On Windows, use .dll:

export CSV_EXTENSION_PATH=/path/to/csv.dll

Or use the CLI flag:

db-mcp --sqlite-native ./data.db --csv

SpatiaLite Extension:

Install the library for your platform:

• Linux (apt): sudo apt install libspatialite-dev
• macOS (Homebrew): brew install libspatialite
• Windows: Download from https://www.gaia-gis.it/gaia-sins/

Set the environment variable:

export SPATIALITE_PATH=/path/to/mod_spatialite.so

Or use the CLI flag:

db-mcp --sqlite-native ./data.db --spatialite

Note: Extension binaries must match your platform and architecture. The server searches common paths automatically, or use the CSV_EXTENSION_PATH / SPATIALITE_PATH environment variables for custom locations.

📁 Resources

Data Resources (11)

MCP resources provide read-only access to database metadata:

Resource	URI	Description	Min Config
sqlite_schema	sqlite://schema	Full database schema	minimal
sqlite_tables	sqlite://tables	List all tables	minimal
sqlite_table_schema	sqlite://table/{tableName}/schema	Schema for a specific table	minimal
sqlite_indexes	sqlite://indexes	All indexes in the database	minimal
sqlite_views	sqlite://views	All views in the database	core,admin
sqlite_health	sqlite://health	Database health and status	(read-only)
sqlite_meta	sqlite://meta	Database metadata and PRAGMAs	core,admin
sqlite_compile_options	sqlite://compile_options	SQLite compile-time build options	(read-only)
sqlite_pragma	sqlite://pragma	Runtime PRAGMA config snapshot	(read-only)
sqlite_audit	sqlite://audit	Recent audit log + backup stats	--audit-log
sqlite_metrics	sqlite://metrics	Internal server metrics	(read-only)

Help Resources (1 + up to 10)

On-demand tool reference documentation, filtered by --tool-filter:

Resource	URI	Description	When Registered
sqlite_help	sqlite://help	Gotchas, WASM vs Native, Code Mode API	Always
sqlite_help_core	sqlite://help/core	Core CRUD and table operations reference	When core group on
sqlite_help_json	sqlite://help/json	JSON/JSONB operations reference	When json group on
sqlite_help_text	sqlite://help/text	Text processing + FTS5 reference	When text group on
sqlite_help_stats	sqlite://help/stats	Statistical analysis + window functions reference	When stats group on
sqlite_help_vector	sqlite://help/vector	Vector/semantic search reference	When vector group on
sqlite_help_geo	sqlite://help/geo	Geospatial + SpatiaLite reference	When geo group on
sqlite_help_admin	sqlite://help/admin	Admin, backup, virtual tables reference	When admin group on
sqlite_help_transactions	sqlite://help/transactions	Transaction control reference	When transactions group on
sqlite_help_introspection	sqlite://help/introspection	Schema introspection, FK graph, diagnostics reference	When introspection group on
sqlite_help_migration	sqlite://help/migration	Migration tracking, apply, rollback reference	When migration group on

Efficiency Tip: Data resources are always readable regardless of tool configuration. The "Min Config" column shows the smallest configuration that provides tools to act on what the resource exposes. Help resources are served on-demand — agents read them only when working with a specific tool group.

💬 Prompts (10)

MCP prompts provide AI-assisted database workflows:

Prompt	Description
sqlite_explain_schema	Explain database structure and relationships
sqlite_query_builder	Help construct SQL queries for common operations
sqlite_data_analysis	Analyze data patterns and provide insights
sqlite_optimization	Analyze and suggest database optimizations
sqlite_migration	Help create database migration scripts
sqlite_debug_query	Debug SQL queries that aren't working
sqlite_documentation	Generate documentation for the database schema
sqlite_summarize_table	Intelligent table analysis and summary
sqlite_hybrid_search_workflow	Hybrid FTS5 + vector search workflow
sqlite_demo	Interactive demo of MCP capabilities

🔧 Configuration

Environment Variables

Variable	Default	Description
MCP_HOST	127.0.0.1	Host/IP to bind to (0.0.0.0 in Docker) (CLI: --server-host)
SQLITE_DATABASE	—	SQLite database path (CLI: --sqlite / --sqlite-native)
DB_ENCRYPTION_KEY	—	SQLCipher encryption key (Native only) (CLI: --encryption-key)
DB_MCP_TOOL_FILTER	—	Tool filter string (CLI: --tool-filter)
METRICS_EXPORT	—	Export metrics at HTTP /metrics (e.g., prometheus) (CLI: --metrics-export)
OAUTH_ENABLED	false	Enable OAuth 2.1 (CLI: --oauth-enabled)
OAUTH_ISSUER	—	Authorization server URL (CLI: --oauth-issuer)
OAUTH_AUDIENCE	—	Expected token audience (CLI: --oauth-audience)
OAUTH_JWKS_URI	—	JWKS URI, auto-discovered if omitted (CLI: --oauth-jwks-uri)
OAUTH_CLOCK_TOLERANCE	60	Clock tolerance in seconds (CLI: --oauth-clock-tolerance)
MCP_ENABLE_HSTS	false	Enable HSTS header (CLI: --enable-hsts)
NO_AUTH_ENFORCEMENT	false	Explicitly bypass auth enforcement for HTTP (CLI: --no-auth-enforcement)
LOG_LEVEL	info	Log verbosity: debug, info, warning, error
METADATA_CACHE_TTL_MS	5000	Schema cache TTL in ms (auto-invalidated on DDL operations)
CODEMODE_ISOLATION	isolate	Code Mode sandbox: isolate (isolated-vm native) or worker
CODE_MODE_MAX_RESULT_SIZE	102400	Maximum Code Mode result payload in bytes (default 100KB, cap 50MB)
MCP_RATE_LIMIT_MAX	100	Max requests/minute per IP (HTTP transport)
CSV_EXTENSION_PATH	—	Custom path to CSV extension binary (native only)
SPATIALITE_PATH	—	Custom path to SpatiaLite extension binary (native only)
ALLOWED_IO_ROOTS	—	JSON array or comma-separated list of absolute paths allowed for IO operations
MCP_AUTH_TOKEN	—	Simple bearer token for HTTP auth (CLI: --auth-token)
AUDIT_LOG	—	Audit log file path, or stderr (CLI: --audit-log)
AUDIT_REDACT	true	Redact tool arguments from audit entries (CLI: --audit-no-redact to disable)
AUDIT_READS	false	Also log read-scoped tool invocations (CLI: --audit-reads)
AUDIT_BACKUP	false	Enable pre-mutation DDL snapshots (CLI: --audit-backup)
AUDIT_BACKUP_DATA	false	Include sample data rows in snapshots (CLI: --audit-backup-data)

Tip: Lower METADATA_CACHE_TTL_MS for development (e.g., 1000), or increase it for production with stable schemas (e.g., 60000 = 1 min). Schema cache is automatically invalidated on DDL operations (CREATE/ALTER/DROP).

CLI Reference

db-mcp [options]

Transport:    --transport <stdio|http|sse>  --port <N>  --server-host <host>  --stateless
Auth:         --oauth-enabled --oauth-issuer <url> --oauth-audience <aud>
Database:     --sqlite <path>  |  --sqlite-native <path>  [--encryption-key <key>]
Extensions:   --csv  --spatialite                         (native only)
Security:     --allowed-io-roots <paths>
Audit:        --audit-log <path>  --audit-no-redact  --audit-reads  --audit-backup  --audit-backup-data
Server:       --name <name>  --version <ver>  --metrics-export <type>  --tool-filter <filter>

CLI flags override environment variables. Run node dist/cli.js --help for full details.

📚 MCP Client Configuration

Add to your ~/.cursor/mcp.json, Claude Desktop config, or equivalent:

{
  "mcpServers": {
    "db-mcp-sqlite": {
      "command": "node",
      "args": [
        "C:/path/to/db-mcp/dist/cli.js",
        "--transport",
        "stdio",
        "--sqlite-native",
        "C:/path/to/your/database.db",
        "--tool-filter",
        "codemode"
      ]
    }
  }
}

[!TIP] Switching backends: The config above uses the Native backend (better-sqlite3, 181 MCP tools). To use the WASM backend (sql.js, 154 MCP tools, zero native dependencies), change --sqlite-native to --sqlite in the args array. See the Backend Options table in DOCKER_README for feature differences.

Variants (modify the args array above):

Variant	Change
WASM backend	Replace --sqlite-native with --sqlite
In-memory database	Replace the database path with :memory:
Starter preset	Replace "codemode" with "starter" for individual tool calls
CSV extension	Add "--csv" before "--tool-filter" (native only)
SpatiaLite	Add "--spatialite" and set env: { "SPATIALITE_PATH": "/path/to/mod_spatialite" } (native only)
Linux/macOS	Use forward-slash Unix paths (e.g., /path/to/db-mcp/dist/cli.js)
Docker	Replace "command": "node" with "command": "docker" and wrap args in run -i --rm -v ./data:/app/data writenotenow/db-mcp:latest

See Tool Filtering to customize which tools are exposed.

🌐 HTTP/SSE Transport (Remote Access)

For remote access, web-based clients, or HTTP-compatible MCP hosts, use the HTTP transport:

node dist/cli.js \
  --transport http \
  --port 3000 \
  --sqlite-native ./database.db \
  --allowed-io-roots $(pwd)

Docker:

docker run --rm -p 3000:3000 \
  -v ./data:/app/data \
  writenotenow/db-mcp:latest \
  --transport http --port 3000 \
  --sqlite-native /app/data/database.db \
  --allowed-io-roots /app/data

The server supports two MCP transport protocols simultaneously, enabling both modern and legacy clients to connect:

Streamable HTTP (Recommended)

Modern protocol (MCP 2025-03-26) — single endpoint, session-based:

Method	Endpoint	Purpose
POST	/mcp	JSON-RPC requests (initialize, tools/list, etc.)
GET	/mcp	SSE stream for server notifications
DELETE	/mcp	Session termination

Sessions are managed via the Mcp-Session-Id header.

Stateless Mode

For serverless/stateless deployments where sessions are not needed:

node dist/cli.js --transport http --port 3000 --stateless --sqlite-native ./database.db --allowed-io-roots $(pwd)

In stateless mode: GET /mcp returns 405, DELETE /mcp returns 204, /sse and /messages return 404. Each POST /mcp creates a fresh transport.

Legacy SSE (Backward Compatibility)

Legacy protocol (MCP 2024-11-05) — for clients like Python mcp.client.sse:

Method	Endpoint	Purpose
GET	/sse	Opens SSE stream, returns /messages?sessionId=<id> endpoint
POST	/messages?sessionId=<id>	Send JSON-RPC messages to the session

Utility Endpoints

Method	Endpoint	Purpose
GET	/health	Health check (bypasses rate limiting, always available for monitoring)

🔐 Authentication

db-mcp secures the HTTP transport using strict OAuth 2.1 authentication:

OAuth 2.1 (Enterprise)

Full OAuth 2.1 with RFC 9728/8414 compliance for production multi-tenant deployments:

node dist/cli.js \
  --transport http \
  --port 3000 \
  --sqlite-native ./database.db \
  --allowed-io-roots $(pwd) \
  --oauth-enabled \
  --oauth-issuer http://localhost:8080/realms/db-mcp \
  --oauth-audience db-mcp-server

Additional flags: --oauth-jwks-uri <url> (auto-discovered if omitted), --oauth-clock-tolerance <seconds> (default: 60).

OAuth Scopes

Access control is managed through OAuth scopes:

Scope	Description
full	Unrestricted access to all operations
read	Read-only access to all databases
write	Read and write access to all databases
admin	Full administrative access

RFC Compliance

This implementation follows:

• RFC 9728 — OAuth 2.1 Protected Resource Metadata
• RFC 8414 — OAuth 2.1 Authorization Server Metadata
• RFC 7591 — OAuth 2.1 Dynamic Client Registration

The server exposes metadata at /.well-known/oauth-protected-resource.

Note for Keycloak users: Add an Audience mapper to your client (Client → Client scopes → dedicated scope → Add mapper → Audience) to include the correct aud claim in tokens.

[!NOTE] Per-tool scope enforcement: Scopes are enforced at the tool level — each tool group maps to a required scope (read, write, or admin). Unknown or unmapped tools default to admin (fail-closed). When OAuth is enabled, every tool invocation checks the calling token's scopes before execution. When OAuth is not configured, scope checks are skipped entirely.

[!TIP] Audit identity integration: When OAuth is enabled alongside audit logging (--audit-log), audit entries for write/admin tools automatically capture the authenticated user (claims.sub) and granted scopes. This provides a complete forensic trail linking every mutation to a specific identity. Without OAuth, these fields are null/[].

[!WARNING] HTTP without authentication: When using --transport http without enabling OAuth, all clients have full unrestricted access. Always enable authentication for production HTTP deployments. See SECURITY.md for details.

🔐 Encryption at Rest (Native Only)

db-mcp supports transparent database encryption using SQLCipher via the better-sqlite3-multiple-ciphers driver. When encryption is enabled, the server automatically encrypts both your target database (if newly created) and the sidecar SystemDb audit log, ensuring your schema, queries, and results are protected at rest.

Important WASM Limitation: The WASM backend (sql.js) does not support encryption. If you supply an encryption key to the WASM backend, it will gracefully ignore it for the target database. However, this can cause conflicts if both a Native and WASM backend share the same --audit-log file (since the Native backend will encrypt the shared audit log, causing the WASM backend to crash when reading it). To avoid this in dual-backend setups, assign a separate audit log (e.g., --audit-log mcp-audit-wasm.db) for your WASM instance.

Configuring the Key: You can provide the key via the --encryption-key CLI flag or the DB_ENCRYPTION_KEY environment variable.

1. Strong Passphrase: A standard string. SQLCipher will automatically use PBKDF2 key derivation.

   DB_ENCRYPTION_KEY="your-strong-passphrase-here"
   

2. Raw Hex Key (Best Performance): To skip PBKDF2 derivation overhead, provide an exact 256-bit raw hex key prefixed with x and wrapped in single quotes:

   DB_ENCRYPTION_KEY="x'2DD29CA851E7B56E4697B0E1F08507293D761A05CE4D1B628663F411A8086D99'"
   

[!WARNING] Audit Log Compatibility: The DB_ENCRYPTION_KEY environment variable applies globally and will cause the internal SystemDb to attempt to decrypt your audit log (--audit-log). If you have an existing unencrypted audit log, the server will fail to start with file is not a database. To encrypt ONLY your target database (leaving the audit log unencrypted), use the --encryption-key CLI flag instead of the global environment variable.

📊 Benchmarks

Performance benchmarks measure framework overhead on critical hot paths using Vitest bench (tinybench). The suite validates that framework plumbing stays negligible relative to actual database I/O:

• Tool dispatch: 6–14M ops/sec — Map-based lookup is effectively zero-cost
• Auth scope checks: 4–8M ops/sec — OAuth middleware adds no measurable latency
• Identifier validation: 4–7M ops/sec — SQL sanitization is near-instant
• Schema cache hits: 3–6M ops/sec — metadata lookups avoid redundant queries
• Debug log (filtered): 5–11M ops/sec — disabled log levels are true no-ops
• Code Mode security: ~0.2–1.3M validations/sec for typical code, blocked patterns rejected in 1-2 µs
• Sandbox execution: ~0.5–4.9K executions/sec — trivial code round-trips through V8 isolate in 0.2-1.5 ms

pnpm run bench            # Run all benchmarks
pnpm run bench:verbose    # Verbose mode with detailed timings

Benchmark	What It Measures
Handler Dispatch	Tool lookup, error construction, progress notification overhead
Utilities	Identifier sanitization, WHERE clause validation, SQL validation
Tool Filtering	Filter parsing, group lookups, meta-group catalog generation
Schema Parsing	Zod schema validation for simple/complex/large payloads + failure paths
Logger & Sanitization	Log call overhead, message sanitization, sensitive data redaction
Transport & Auth	Token extraction, scope checking, error formatting, rate limiting
Code Mode	Sandbox creation, pool lifecycle, security validation, execution
Database Operations	PRAGMA ops, table metadata, query result processing, schema caching
Resource & Prompts	URI matching, content assembly, prompt generation, tool indexing

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Contributing

Contributions are welcome! Please read our Contributing Guidelines before submitting a pull request.

Security

For security concerns, please see our Security Policy.

⚠️ Never commit credentials - Store secrets in .env (gitignored)

License

This project is licensed under the MIT License - see the LICENSE file for details.

Code of Conduct

Please read our Code of Conduct before participating in this project.