A Model Context Protocol (MCP) server for managing prompt templates with dynamic variable substitution. This server provides tools for saving, updating, retrieving, and managing reusable prompt templates with automatic variable extraction.
- Dynamic Variable Extraction: Automatically detects
{variable}placeholders in templates - MCP Tools: Full set of tools for template management accessible via MCP clients
- REST API: HTTP endpoints for integration with external applications
- Persistent Storage: Uses Cloudflare D1 database for reliable storage
- Variable Substitution: Render templates with provided input values
The server exposes the following MCP tools:
save_prompt_template- Save new templates with automatic input extractionupdate_prompt_template- Modify existing templatesdelete_prompt_template- Remove templateslist_prompt_templates- View all saved templatesget_prompt_by_name- Retrieve and render templates with input values
// Save a template
await save_prompt_template({
name: "greeting",
template: "Hello my name is {firstName} {lastName}. What is my name?"
});
// Automatically extracts: firstName, lastName as required inputs
// Use the template
await get_prompt_by_name({
name: "greeting",
inputs: {
firstName: "John",
lastName: "Doe"
}
});
// Returns: "Hello my name is John Doe. What is my name?"GET /prompts- List all templatesGET /prompts/:name- Get a specific templatePOST /prompts- Create a new templatePUT /prompts/:name- Update a templateDELETE /prompts/:name- Delete a template
This project uses the HONC stack (Hono + Cloudflare) with D1 database for storage.
├── src
│ ├── index.ts # MCP server & API endpoints
│ └── db
│ └── schema.ts # Database schema for prompt templates
├── wrangler.toml # Cloudflare Workers configuration
├── drizzle.config.ts # Drizzle ORM configuration
├── package.json
└── tsconfig.json
Run the migrations and (optionally) seed the database:
# this is a convenience script that runs db:touch, db:generate, db:migrate, and db:seed
npm run db:setupRun the development server:
npm run devAs you iterate on the database schema, you'll need to generate a new migration file and apply it like so:
npm run db:generate
npm run db:migrateBefore deploying your worker to Cloudflare, ensure that you have a running D1 instance on Cloudflare to connect your worker to.
You can create a D1 instance by navigating to the Workers & Pages section and selecting D1 SQL Database.
Alternatively, you can create a D1 instance using the CLI:
npx wrangler d1 create <database-name>After creating the database, update the wrangler.toml file with the database id.
[[d1_databases]]
binding = "DB"
database_name = "honc-d1-database"
database_id = "<database-id-you-just-created>"
migrations_dir = "drizzle/migrations"Include the following information in a .prod.vars file:
CLOUDFLARE_D1_TOKEN="" # An API token with D1 edit permissions. You can create API tokens from your Cloudflare profile
CLOUDFLARE_ACCOUNT_ID="" # Find your Account id on the Workers & Pages overview (upper right)
CLOUDFLARE_DATABASE_ID="" # Find the database ID under workers & pages under D1 SQL Database and by selecting the created databaseIf you haven’t generated the latest migration files yet, run:
npm run db:generateAfterwards, run the migration script for production:
npm run db:migrate:prodChange the name of the project in wrangler.toml to something appropriate for your project:
name = "prompt-templates-mcp"Finally, deploy your worker:
npm run deployThe server uses a simple schema to store prompt templates:
promptTemplates {
id: integer (primary key)
name: text (unique)
template: text
inputs: text (JSON array of required variables)
createdAt: text
updatedAt: text
}After deploying your server, follow these steps to connect it to Claude Desktop:
-
Open Claude Desktop Configuration
- On macOS:
~/Library/Application Support/Claude/claude_desktop_config.json - On Windows:
%APPDATA%\Claude\claude_desktop_config.json
- On macOS:
-
Add your MCP server to the configuration file:
{
"mcpServers": {
"prompt-templates": {
"command": "npx",
"args": [
"@modelcontextprotocol/server-fetch",
"https://YOUR-WORKER-URL/mcp"
]
}
}
}Replace YOUR-WORKER-URL with your deployed Cloudflare Worker URL.
-
Restart Claude Desktop completely (quit and reopen the application)
-
Verify the connection by looking for the 🔌 icon in Claude Desktop, which indicates MCP servers are connected
Once connected, you can use these tools in your conversations:
Save a template:
Use the save_prompt_template tool to save this template:
- Name: "greeting"
- Description: "A personalized greeting template"
- Template: "Hello my name is {firstName} {lastName}. What is my name?"
List your templates:
Use the list_prompt_templates tool to show me all saved templates
Use a template:
Use the get_prompt_by_name tool with:
- Name: "greeting"
- Inputs: {"firstName": "John", "lastName": "Doe"}
The server will automatically extract variables from any template you save (like {firstName} and {lastName} from your example) and make them available as structured inputs.
- Hono - Web framework
- Cloudflare Workers - Serverless platform
- Cloudflare D1 - SQLite database
- Drizzle ORM - TypeScript ORM
- Model Context Protocol - AI tool integration protocol