#!/usr/bin/env -S deno run --allow-net --allow-read --allow-write --allow-env
// SPDX-License-Identifier: PMPL-1.0-or-later
// SPDX-FileCopyrightText: 2025 Jonathan D.A. Jewell
/**
* Polyglot DB MCP Server
* Unified interface to multiple databases
*
* Run: deno task start
*/
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
// Import all adapters
import * as surrealdb from "./adapters/surrealdb.js";
import * as dragonfly from "./adapters/dragonfly.js";
import * as xtdb from "./adapters/xtdb.js";
import * as sqlite from "./adapters/sqlite.js";
import * as duckdb from "./adapters/duckdb.js";
import * as qdrant from "./adapters/qdrant.js";
import * as meilisearch from "./adapters/meilisearch.js";
import * as mariadb from "./adapters/mariadb.js";
import * as memcached from "./adapters/memcached.js";
import * as lmdb from "./adapters/lmdb.js";
import * as itop from "./adapters/itop.js";
import * as postgresql from "./adapters/postgresql.js";
import * as mongodb from "./adapters/mongodb.js";
import * as neo4j from "./adapters/neo4j.js";
import * as elasticsearch from "./adapters/elasticsearch.js";
import * as influxdb from "./adapters/influxdb.js";
import * as arangodb from "./adapters/arangodb.js";
import * as virtuoso from "./adapters/virtuoso.js";
import * as couchdb from "./adapters/couchdb.js";
import * as cassandra from "./adapters/cassandra.js";
import * as verisimdb from "./adapters/verisimdb.js";
// Registry of all adapters
const adapters = {
surrealdb,
dragonfly,
xtdb,
sqlite,
duckdb,
qdrant,
meilisearch,
mariadb,
memcached,
lmdb,
itop,
postgresql,
mongodb,
neo4j,
elasticsearch,
influxdb,
arangodb,
virtuoso,
couchdb,
cassandra,
verisimdb,
};
const server = new McpServer({
name: "polyglot-db-mcp",
version: "1.1.0",
});
// =============================================================================
// UNIFIED TOOLS - Work across all databases
// =============================================================================
server.tool(
"db_list",
{
checkConnections: {
type: "boolean",
description: "Check which databases are actually connected (slower)",
},
},
async ({ checkConnections = false }) => {
const databases = [];
for (const [name, adapter] of Object.entries(adapters)) {
const db = {
name,
description: adapter.description,
tools: Object.keys(adapter.tools || {}),
};
if (checkConnections) {
try {
db.connected = await adapter.isConnected();
} catch {
db.connected = false;
}
}
databases.push(db);
}
return {
content: [
{
type: "text",
text: JSON.stringify({ databases, total: databases.length }, null, 2),
},
],
};
}
);
server.tool(
"db_help",
{
database: {
type: "string",
description: "Database name to get help for (optional, shows all if omitted)",
},
},
async ({ database }) => {
if (database) {
const adapter = adapters[database];
if (!adapter) {
return {
content: [
{
type: "text",
text: `Unknown database: ${database}. Use db_list to see available databases.`,
},
],
};
}
const tools = Object.entries(adapter.tools || {}).map(([name, tool]) => ({
name,
description: tool.description,
params: Object.entries(tool.params || {}).map(([pname, pdef]) => ({
name: pname,
...pdef,
})),
}));
return {
content: [
{
type: "text",
text: JSON.stringify(
{
database,
description: adapter.description,
tools,
},
null,
2
),
},
],
};
}
// Show summary of all databases
const summary = Object.entries(adapters).map(([name, adapter]) => ({
name,
description: adapter.description,
toolCount: Object.keys(adapter.tools || {}).length,
}));
return {
content: [
{
type: "text",
text: JSON.stringify({ databases: summary }, null, 2),
},
],
};
}
);
server.tool(
"db_status",
{},
async () => {
const status = {};
for (const [name, adapter] of Object.entries(adapters)) {
try {
status[name] = await adapter.isConnected();
} catch {
status[name] = false;
}
}
const connected = Object.entries(status)
.filter(([, v]) => v)
.map(([k]) => k);
const disconnected = Object.entries(status)
.filter(([, v]) => !v)
.map(([k]) => k);
return {
content: [
{
type: "text",
text: JSON.stringify(
{
connected,
disconnected,
summary: `${connected.length}/${Object.keys(status).length} databases connected`,
},
null,
2
),
},
],
};
}
);
// =============================================================================
// REGISTER ALL ADAPTER TOOLS
// =============================================================================
for (const [adapterName, adapter] of Object.entries(adapters)) {
for (const [toolName, toolDef] of Object.entries(adapter.tools || {})) {
// Convert params to the format expected by MCP
const params = {};
for (const [paramName, paramDef] of Object.entries(toolDef.params || {})) {
params[paramName] = paramDef;
}
server.tool(toolName, params, async (args) => {
try {
const result = await toolDef.handler(args);
return {
content: [
{
type: "text",
text: JSON.stringify(result, null, 2),
},
],
};
} catch (error) {
const feedbackUrl = `https://github.com/hyperpolymath/poly-db-mcp/issues/new?title=${encodeURIComponent(`[BUG] ${toolName}: ${error.message.substring(0, 50)}`)}&labels=bug&body=${encodeURIComponent(`## Error Details\n- **Tool**: ${toolName}\n- **Adapter**: ${adapterName}\n- **Error**: ${error.message}\n\n## Environment\n- OS: \n- Deno version: \n\n## Steps to Reproduce\n1. \n\n## Additional Context\n`)}`;
return {
content: [
{
type: "text",
text: JSON.stringify({
error: error.message,
tool: toolName,
adapter: adapterName,
feedback: {
message: "🐛 Found a bug? This is early development - your feedback helps!",
reportUrl: feedbackUrl,
},
}, null, 2),
},
],
};
}
});
}
}
// =============================================================================
// CROSS-DATABASE TOOLS
// =============================================================================
server.tool(
"db_copy",
{
from_db: { type: "string", description: "Source database name" },
from_query: { type: "string", description: "Query to get source data (db-specific)" },
to_db: { type: "string", description: "Target database name" },
to_target: { type: "string", description: "Target location (table/collection/key prefix)" },
transform: { type: "string", description: "JS transform function as string (optional)" },
},
async ({ from_db, from_query, to_db, to_target, transform }) => {
// This is a simplified cross-DB copy - real implementation would be more complex
return {
content: [
{
type: "text",
text: JSON.stringify({
message: "Cross-database copy requires specific implementation per DB pair",
hint: "Use the individual query and insert tools for now",
from: from_db,
to: to_db,
}, null, 2),
},
],
};
}
);
// =============================================================================
// START SERVER
// =============================================================================
const transport = new StdioServerTransport();
await server.connect(transport);
