askDB
askDB MCP
Un servidor MCP que convierte preguntas de datos en lenguaje natural en el contexto de esquema que un LLM necesita para escribir SQL. No se conecta a tu base de datos y no genera SQL por sí mismo: recupera las definiciones de tabla correctas de tu índice de Pinecone y se las entrega al modelo que las solicite (Claude Code, Claude Desktop, ChatGPT, Cursor).
user question
│
▼
Claude Code / ChatGPT ──calls──► askDB MCP ──semantic search──► Pinecone (ask-db)
│ │
│ relevant DDL + guardrails ◄─┘
▼
generated SQLHerramientas
Herramienta | Cuándo la usa el modelo | Entrada |
| Primera llamada para cualquier solicitud de texto a SQL |
|
| Necesita todas las columnas de una tabla conocida |
|
| Orientación, o cuando la búsqueda vuelve vacía |
|
Cada respuesta incluye instrucciones que le indican al modelo que use solo las tablas y columnas devueltas, para que no invente nombres.
Related MCP server: Vanna AI MCP Server
Configuración
npm install
npm run setup # creates .env from the template
# → then put your PINECONE_API_KEY in .env
npm run doctor # verify connection, field mapping and retrieval quality¿Compartes esto con alguien? Envíale SETUP.md: cubre tanto ejecutarlo localmente como conectarse a una instancia alojada.
npm run doctor es el paso importante. Imprime la configuración del índice, los campos de metadatos que usan realmente tus registros y una búsqueda de ejemplo, para que puedas confirmar que el servidor está leyendo los campos correctos antes de conectarlo a un cliente.
npm run doctor # connectivity + retrieval sanity check
npm run smoke # drive the stdio server with a real MCP client
npm run smoke:http # same over Streamable HTTP, with bearer authConectar un cliente
Claude Code
La CLI, la aplicación de escritorio y las extensiones del IDE comparten una misma configuración, así que esto registra el servidor para los tres:
# from the repo root — records an absolute path, so it works in any folder
claude mcp add askdb --scope user -- node "$PWD\src\server.js"Compruébalo con claude mcp list (askdb: ... ✓ Connected) y reinicia la aplicación de escritorio o la ventana del IDE: los servidores MCP se cargan al inicio.
El ámbito de usuario es deliberado: la idea es hacer preguntas sobre bases de datos mientras trabajas en tus otros repositorios. Un .mcp.json con ámbito de proyecto solo se resolvería cuando Claude Code se inicia desde la raíz de este repositorio, y definir askdb en ambos ámbitos haría que Claude Code advierta sobre el duplicado.
Claude Desktop / Cursor
Añade a claude_desktop_config.json (o a los ajustes MCP de Cursor):
{
"mcpServers": {
"askdb": {
"command": "node",
"args": ["D:\\working-directory\\AI\\askDB-mcp\\src\\server.js"]
}
}
}Las credenciales provienen de .env junto al servidor, así que no van claves en la configuración del cliente.
ChatGPT
Los conectores de ChatGPT no pueden lanzar un proceso local: solo hablan MCP remoto sobre HTTP. Ejecuta el transporte HTTP y exponlo:
# set MCP_AUTH_TOKEN first: this endpoint serves your whole schema
MCP_AUTH_TOKEN=some-long-random-string npm run start:httpLuego apunta el conector a https://<tu-host>/mcp con una cabecera Authorization: Bearer <token>. Para una prueba rápida, haz un túnel (cloudflared tunnel --url http://localhost:3000); para algo duradero, alójalo correctamente: DEPLOY.md cubre Netlify de principio a fin. GET /health no requiere autenticación para las comprobaciones del balanceador de carga; /mcp requiere el token bearer siempre que MCP_AUTH_TOKEN esté definido.
El transporte HTTP no tiene estado (una instancia del servidor por solicitud), por lo que escala detrás de un balanceador de carga sin sesiones persistentes.
Alojamiento
Desplegado como dos funciones de Netlify: netlify.toml contiene los ajustes de compilación, así que importar el repositorio y definir PINECONE_API_KEY + MCP_AUTH_TOKEN es todo el trabajo. Paso a paso: DEPLOY.md.
Esto funciona sin reescribir el transporte porque WebStandardStreamableHTTPServerTransport del SDK de MCP acepta una Request y devuelve una Response, que es la firma de Netlify Functions v2, de modo que netlify/functions/mcp.mjs importa src/mcp.js sin cambios. El mismo archivo funciona en Cloudflare Workers, Deno o Bun; src/http.js cubre contenedores y máquinas virtuales.
GET /health no necesita token e informa si las variables de entorno requeridas llegaron (solo presencia, nunca valores): el sustituto serverless de leer un registro de inicio. /mcp falla de forma segura: sin MCP_AUTH_TOKEN definido devuelve 503 en lugar de servir tu esquema a internet.
Una vez que está en marcha, los compañeros no necesitan instalar nada: solo la URL y un token (SETUP.md, Ruta A).
Configuración
Todo es opcional excepto la clave de API. Consulta .env.example.
Variable | Default | Notas |
| — | Requerida |
|
| |
| (espacio de nombres predeterminado) | |
|
| Fragmentos de esquema por búsqueda |
|
| Debe coincidir con el modelo con el que hiciste el upsert |
| (desactivado) | p. ej. |
| (todas) | Limita cada búsqueda a una base de datos |
|
| Se pasa al modelo como sugerencia |
| consulta | Claves de metadatos candidatas, probadas en orden |
|
| Límite para el escaneo de |
El servidor detecta automáticamente qué campos de metadatos usan tus registros y si el índice tiene embedding integrado, así que los valores predeterminados normalmente funcionan sin cambios.
Dos cosas que conviene saber
El modelo de embedding debe coincidir. Si EMBED_MODEL no es el modelo con el que se hizo el upsert del esquema, todas las puntuaciones caen a casi cero y los resultados son ruido: los vectores son efectivamente aleatorios entre sí. npm run doctor mostrará tablas no relacionadas que vuelven con puntuaciones alrededor de 0.01 en lugar de 0.8. Este índice se construyó con multilingual-e5-large.
Define DEFAULT_DATABASE si tu índice contiene varios entornos. Cuando el mismo esquema existe como *_live y *_test, una búsqueda sin ámbito devuelve ambas copias de cada tabla, quemando la mitad de los espacios de top_k en duplicados y permitiendo que el modelo mezcle entornos en una sola consulta.
Estructura
Archivo | Rol |
Definiciones de herramientas: la superficie MCP | |
Recuperación: búsqueda, obtención exacta, detección de campos, rerank | |
Convierte los resultados en el bloque de esquema que lee el modelo | |
Punto de entrada stdio | |
Punto de entrada HTTP de transmisión | |
Carga de variables de entorno y valores predeterminados | |
Diagnósticos de conectividad y recuperación | |
Puntos de entrada serverless: | |
Configuración de compilación y enrutamiento de Netlify | |
Guía de alojamiento |
Available Tools
3 toolsget_table_schemaGet schema for specific tablesARead-only
Fetch the full stored DDL for one or more tables by exact name. Use after search_schema when you need every column of a table, or when the user named the table.
| Name | Required | Description | Default |
|---|---|---|---|
| tables | Yes | Exact table names, e.g. ["tbl_account", "tbl_order"]. | |
| database | No | Restrict to one database/schema — omit to search all of them. | |
| namespace | No | Pinecone namespace override. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool as read-only and open-world, so the behavioral burden is lower. The description clarifies that DDL is returned for exact table names, but does not add details like pagination limits, error handling for missing tables, or performance traits beyond what annotations signal.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise—two short sentences that immediately convey purpose and usage context. There is no wasted wording, and every sentence adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity, strong annotations, and complete schema, the description is largely complete. It could optionally mention that the output is raw DDL (though implicit), but lack of output schema does not diminish clarity given the straightforward fetch operation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already thoroughly documents all three parameters. The description adds no extra semantics beyond what the schema provides, so a baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool fetches 'full stored DDL for one or more tables by exact name', using specific verbs and resources. It also distinguishes itself from sibling tool 'search_schema' by indicating when to use this tool after that one.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides explicit guidance on when to use this tool ('after search_schema when you need every column') and references the user naming a table. However, it does not explicitly state when not to use it or mention any alternatives like 'list_tables'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
list_tablesList available tablesARead-only
Inventory of every table in the schema index, grouped by database, plus the index configuration. Use it to orient yourself, or when search_schema comes back empty.
| Name | Required | Description | Default |
|---|---|---|---|
| database | No | Restrict to one database/schema — omit to search all of them. | |
| namespace | No | Pinecone namespace override. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, covering safety and scope. The description adds beyond annotations by stating that results are grouped by database and include index configuration. No behavioral traits (like performance impact or pagination) are discussed, but for a read-only inventory tool this is adequate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with zero wasted words. The first sentence defines the core functionality, and the second provides usage guidance. It is front-loaded and every part earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple list tool with no output schema, the description gives a sufficient mental model: inventory, grouping by database, and inclusion of index configuration. Could be slightly more explicit about the return structure (e.g., whether it's flat or nested), but fine given the tool's simplicity and the presence of sibling context.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with clear descriptions for both optional parameters (database filter and namespace override). The description does not elaborate further on parameter semantics beyond what the schema provides, so it meets the baseline expected when schema does the heavy lifting.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool provides an 'Inventory of every table in the schema index, grouped by database, plus the index configuration.' It uses specific verbs and nouns, and distinguishes itself from sibling tools like search_schema by indicating when to use it (when search_schema returns empty).
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly says 'Use it to orient yourself, or when search_schema comes back empty,' providing clear usage context. It does not mention when to avoid this tool or use get_table_schema, but the positive guidance is strong and helps an agent decide between siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
search_schemaSearch database schemaARead-only
Semantic search over the database schema stored in Pinecone. Call this FIRST for any text-to-SQL request: pass the user question verbatim and you get back the relevant tables, columns, types and relationships to write the query against.
| Name | Required | Description | Default |
|---|---|---|---|
| top_k | No | How many schema chunks to retrieve (default 8). | |
| tables | No | Restrict the search to these table names, when you already know them. | |
| database | No | Restrict to one database/schema — omit to search all of them. | |
| question | Yes | The natural-language data question, e.g. "top 10 accounts by transaction volume last month". | |
| namespace | No | Pinecone namespace override. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint=true and openWorldHint=true, so the description's disclosure burden is lower. The description adds context about the Pinecone vector store and the first-step pipeline role, which is valuable beyond annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, no wasted words. The first sentence defines the tool, the second provides usage instruction. Front-loaded and efficient.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
No output schema, but the description indicates what is returned (relevant tables, columns, types, relationships). For a semantic search tool, this is sufficient. The tool is moderately complex (5 params, no nested objects) and the description covers its role adequately.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so all 5 parameters are documented in the schema. The description reinforces the 'question' parameter by saying 'pass the user question verbatim' but does not add new semantics beyond what the schema provides for other parameters. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it performs semantic search over the database schema stored in Pinecone, explicitly for text-to-SQL requests. It distinguishes from siblings by positioning itself as the first step and mentioning retrieval of tables, columns, types, and relationships.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly says 'Call this FIRST for any text-to-SQL request', providing clear context for when to use. It doesn't explicitly exclude alternatives like get_table_schema or list_tables, but the 'first step' instruction implies the workflow.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
3 tool updates
v1.0.0- First observed
get_table_schema - First observed
list_tables - First observed
search_schema
TDQS
Scored across 3 tools
Each tool has a clearly distinct purpose: search_schema for semantic discovery, get_table_schema for exact DDL retrieval, and list_tables for inventory. There is no overlap or ambiguity between them.
All tool names follow a consistent verb_noun pattern in snake_case (search_schema, get_table_schema, list_tables), making them predictable and easy to understand.
Three tools is minimal but appropriate for the focused domain of database schema exploration. Each tool earns its place and covers the essential operations without being overly sparse.
The tool set fully covers schema discovery: semantic search, exact schema lookup, and table listing. For the stated purpose of enabling text-to-SQL by providing schema info, there are no obvious gaps.
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