MCP Blueprint

Build domain-oriented MCP servers without writing Python code for every project.

MCP Blueprint is a lightweight framework for creating Model Context Protocol (MCP) servers from configuration files, SQL queries and metadata instead of custom application code.

Instead of exposing a generic SQL interface, MCP Blueprint exposes a curated set of business-oriented tools that are easier for LLMs to understand, safer to use and simpler to maintain.

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Why?

Many existing MCP database servers expose tools such as:

• execute_sql()
• query_database()

Although powerful, these tools require the LLM to:

• understand the database schema
• write efficient SQL
• know relationships between tables
• respect business rules
• avoid expensive queries

This approach works well for experiments but is often unsuitable for production environments.

MCP Blueprint follows a different philosophy:

Don't expose the database. Expose the domain.

The LLM should ask for information, not write SQL.

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Example

Instead of

execute_sql(...)

an application exposes

get_customer()
get_customer_orders()
get_customer_payments()
search_customer()

or, for database administration,

get_performance_kpis()
get_users()
get_database_sizes()
get_replication_status()

Every tool has a well-defined purpose and hides all SQL complexity.

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Getting started

Install the framework and run the reference server:

uv sync --all-extras --dev
uv run blueprint serve --config config --transport stdio

Or run it in Docker with a bundled PostgreSQL over Streamable HTTP:

docker compose up --build

The server is then available at http://localhost:8000/mcp.

For a full walkthrough see docs/installation.md, docs/quickstart.md and docs/docker.md.

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Architecture

                 +----------------+
                 |    LLM Agent   |
                 +--------+-------+
                          |
                     MCP Protocol
                          |
                  +-------+-------+
                  | MCP Blueprint |
                  +-------+--------+
                          |
          +---------------+----------------+
          |               |                |
      Tool Metadata     SQL Loader    Auth/Logging
          |               |
          +-------+-------+
                  |
           Relational Database

The framework is responsible for

• creating MCP tools
• parameter validation
• database connections
• logging
• error handling
• optional caching
• optional authorization

Application developers only provide configuration files.

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Philosophy

An MCP server should look like a REST API, not like a SQL console.

Each tool should represent a meaningful operation.

Beyond the tool API, MCP Blueprint owns the operational concerns — SQL safety (read-only by default, explicit opt-in for writes, injection-proof parameters), structured logging and telemetry — so pack authors never have to implement them; see the security model, logging, audit and tracing and Prometheus metrics.

Good examples

get_customer()
search_customer()
get_invoice()
get_database_size()

Bad examples

execute_sql()
run_query()

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Project structure

mcp-blueprint/
    blueprint/
    config/
    packs/
    docs/
    examples/
    tests/
    Dockerfile
    docker-compose.yaml

A pack contains everything needed for a specific domain.

Example:

packs/
    pg-dba/
        tools/
        sql/
        pack.yaml
    mysql-dba/
    sakila/
    customer/
    warehouse/

The engine is declared once per pack in pack.yaml (e.g. engines: [postgresql]); packs that do not match the configured engine are skipped, so database.engine selects both the adapter and the loaded packs. A tool may still override per-engine via a sql map for packs that share a tool across engines. template/pack provides a minimal skeleton for authoring new packs and is not auto-loaded.

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Tool definition

Every tool is described using YAML.

Example

name: get_largest_objects
description: Return the largest tables and indexes by size, ordered descending.
sql: ../sql/get_largest_objects.sql

No Python code should be required to create a new tool.

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SQL files

SQL remains external.

sql/
        get_users.sql
        get_database_sizes.sql
        get_largest_objects.sql

Changing the database version or rewriting a query should never require changing Python code.

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Packs

A pack is a reusable collection of tools.

Examples

• PostgreSQL DBA Pack
• MySQL DBA Pack
• Oracle DBA Pack
• Customer Pack
• Sales Pack
• Warehouse Pack
• ERP Pack

Every pack is independent.

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Template pack

template/pack is the minimal skeleton for a new pack (pack metadata, one example tool, one example SQL query). It is not auto-loaded by the framework. To start a new domain pack, copy the template or an existing pack such as packs/sakila and replace tool names, descriptions and SQL. See template/README.md.

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Example pack: Sakila

packs/sakila is the recommended first example: a small, domain-oriented pack for the Sakila sample database on PostgreSQL. It lets an agent run a DVD rental store chatbot — recommend films, inspect a film in detail and review a customer's rental activity — without ever writing SQL.

Tool	Purpose
search_films	Recommend films by optional title, category, rating.
get_film	Full catalog record for one film.
search_customer	Find a customer by first or last name.
get_customer_rentals	Rental history with an active/overdue/returned status.

Domain knowledge lives in SQL, not Python: search_films translates MPAA rating codes into a human-readable rating_label and a numeric min_age, and get_customer_rentals computes the rental status. The tool descriptions steer the agent, e.g. search_customer points at get_customer_rentals to check a customer's situation. See docs/sakila.md for the full walkthrough.

The DBA packs below are more specialized administration packs; study Sakila first to see how a domain pack is built.

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Reference packs

The reference implementations are independent administration packs with the same 13 tools: packs/pg-dba (PostgreSQL 14+) and packs/mysql-dba (MySQL 8+). Each is self-contained and can evolve independently with engine-specific tools.

With database.engine: postgresql the pg-dba and sakila packs load; with database.engine: mysql only mysql-dba loads.

Each pack contains ready-to-use tools for database administration, split into KPI dashboards and detail tools.

KPI dashboards always return rows with a status of ok/warning/error:

• operational KPIs (connection slots, transaction wrap, database growth)
• performance KPIs (cache hit ratio, replication lag, index usage)
• security KPIs (pending SSL, roles with login, password checks)

Detail tools:

• users and roles
• active sessions and connections
• database sizes
• database version
• largest objects
• replication status
• tuning configuration
• slow queries
• maintenance status
• index health

The packs do not expose SQL execution.

Only curated DBA operations. All tools can work with least-privilege monitoring users (e.g. the pg_monitor role on PostgreSQL).

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Design goals

• Configuration-driven
• Database-independent
• Domain-oriented
• Easy to extend
• Safe by default
• Small number of meaningful tools
• SQL separated from Python
• Production-ready

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Long-term vision

MCP Blueprint aims to become for MCP what REST frameworks became for HTTP APIs.

Developers should focus on describing their domain, not implementing infrastructure.

An MCP server should be assembled from reusable packs rather than developed from scratch.

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License

Released under the Apache License 2.0.