TaxJar MCP Server

How to use

You run the MCP server on your machine and connect your AI client to it. The server presents TaxJar data as relational models and provides read-only access. Use natural language prompts to ask about opportunities, invoices, customers, or other TaxJar data you have permission to view. The AI client will handle translating your questions into the built-in MCP tools behind the scenes.

How to install

Prerequisites you need locally: - Java Runtime Environment (JRE) or Java Development Kit (JDK) - Maven for building the MCP server - A browser to complete any OAuth steps during driver setup (if applicable)

1. Clone the project and change into the directory.

git clone https://github.com/cdatasoftware/taxjar-mcp-server-by-cdata.git
cd taxjar-mcp-server-by-cdata

2. Build the MCP server to create the JAR with dependencies.

mvn clean install

3. Download and install the CData JDBC Driver for TaxJar to enable live data access.

https://www.cdata.com/drivers/taxjar/download/jdbc

4. License the CData JDBC Driver using its installer in the lib folder.

java -jar cdata.jdbc.taxjar.jar --license
```
Enter your name, email, and the TRIAL license key when prompted.

5. Configure the JDBC connection using the Connection String utility.

java -jar cdata.jdbc.taxjar.jar
```
Then test the connection and copy the connection string for later use. Note that OAuth may require browser authentication.

6. Create a .prp file for the JDBC connection (example name taxjar.prp) with these properties.

Prefix=taxjar
ServerName=CDataTaxJar
ServerVersion=1.0
DriverPath=PATH\TO\cdata.jdbc.taxjar.jar
DriverClass=cdata.jdbc.taxjar.TaxJarDriver
JdbcUrl=jdbc:taxjar:InitiateOAuth=GETANDREFRESH;
Tables=
```
Replace PATH\TO with the actual path to the driver JAR and adjust the JDBC URL as needed.

Using the server with Claude Desktop

To connect an MCP server to a client like Claude Desktop, add a new MCP server entry in the client’s config under mcpServers. The entry points to the Java runtime and the MCP JAR with the path to your taxjar.prp file.

{
  "mcpServers": {
    "taxjar_mcp": {
      "command": "PATH\\TO\\java.exe",
      "args": [
        "-jar",
        "PATH\\TO\\CDataMCP-jar-with-dependencies.jar",
        "PATH\\TO\\taxjar.prp"
      ]
    }
  }
}
```
Replace PATH with actual locations on Windows. If you are on Linux or macOS, use the Unix-style paths and the corresponding java binary.

After saving the config, restart or refresh the Claude Desktop client so the MCP server appears.

Running the server

Start the MCP server with the following command. It runs locally on the same machine as your client.

java -jar /PATH/TO/CDataMCP-jar-with-dependencies.jar /PATH/TO/taxjar.prp
```
```
Note: The server uses stdio and is intended for clients running on the same machine.

Usage details and tools

After configuration, the AI client queries TaxJar data through built-in tools. You don’t need to call the tools directly; simply ask questions like the examples below and the client will fetch results from TaxJar via the MCP server.

Tool names follow the pattern {servername}_get_tables, {servername}_get_columns, and {servername}_run_query. These tools retrieve available tables, list columns, and execute select queries respectively. The outputs are formatted in CSV where appropriate.

Troubleshooting

If the MCP server does not appear in the client, ensure you have fully quit and restarted the client after adding the new MCP entry.

If data retrieval fails, verify the connection string in taxjar.prp is correct and that the driver is licensed and configured properly.

If you encounter connectivity issues with the data source, contact CData Support for assistance.

License

This MCP server is released under the MIT License. You may use, modify, and distribute it in accordance with MIT terms.

All supported sources

TaxJar data sources are exposed through MCP to enable querying and analysis via the MCP interface.

taxjar_mcp_get_tables

Retrieves a list of tables available in the TaxJar data source. The output is returned in CSV format with headers.

taxjar_mcp_get_columns

Retrieves a list of columns for a specified table. The output is returned in CSV format with headers.

taxjar_mcp_run_query

Executes a SQL SELECT query against the TaxJar data source and returns the results.