---
title: Examples
description: Runnable example extensions for the Actian MCP Server, with configuration and schema files for Actian Analytics Engine.
---

# Examples

Five runnable extensions are published in the documentation repository, ready to mount into a running server. They use only the public extension API.

| Example | What it shows |
|---------|---------------|
| [`catalog_insights.py`](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/extensions/catalog_insights.py) | Read-only tools. Registers `low_stock_products` and `inventory_value`, and reads the authenticated identity. Works in the default read-only mode. |
| [`order_ops.py`](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/extensions/order_ops.py) | Multi-table transactions. `place_order` writes four tables atomically, `cancel_order` restores stock and removes the order, and `order_summary` reads. Needs read-write mode. |
| [`approval_required.py`](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/extensions/approval_required.py) | Human approval. `adjust_stock` asks for confirmation and writes only if you approve. Needs read-write mode and a client that can display the prompt. |
| [`catalog_resources.py`](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/extensions/catalog_resources.py) | The rest of the surface: `setup()` and `teardown()` hooks, a static and a templated resource, and a prompt. Read-only. |
| [`revenue_extension.py`](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/extensions/revenue_extension.py) | All three patterns in one reference example: a read tool, an approval-gated write, and a two-table transaction. |

All five custom extensions share one database. The [Example External Extensions README](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/extensions/README.md) has the full walkthrough.

## Configuration and Schema Files

Analytics Engine has a configuration template and a schema file.

| Database | Configuration template | Schema file |
|----------|------------------------|-------------|
| Analytics Engine | [`conf.example.analytics_engine.json`](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/extensions/conf.example.analytics_engine.json) | [`schema.analytics_engine.sql`](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/extensions/schema.analytics_engine.sql) |

The schema file creates seven tables and seed data. The rule that stock cannot go negative is not enforced at the database level on Analytics Engine, where X100 tables support neither a `CHECK` constraint nor a trigger. The schema file's header lists the grant statements to run afterwards for the account the server connects as.

## Running the Examples

!!! note "Read-write mode required"
    The two transaction examples and the approval example need `"query_mode": "read-write"`. See [Write support](../write-support.md).

Mount each file under `/app/extensions/`, mount your configuration at `/app/conf.json`, and list the modules by name:

```json
{
  "query_mode": "read-write",
  "extensions": [
    { "module": "revenue_extension",
      "config": { "default_region": "NA", "revenue_table": "customer_revenue" } }
  ]
}
```

```bash
docker run -d --rm -p 8000:8000 \
    -e DATABASE_USER=<user> -e DATABASE_PASSWORD=<password> \
    -v ./revenue_extension.py:/app/extensions/revenue_extension.py:ro \
    -v ./conf.json:/app/conf.json:ro \
    <actian-mcp-image>
```

The startup log shows a `Loaded extension` line for each module and one line per registered tool. Those tools then appear in your MCP client's tool list next to the built-in ones.

## Answering the Approval Prompt

Claude Desktop and GitHub Copilot cannot display the write-approval prompt, so writes through them fail closed. To test an approval-gated tool such as `adjust_stock`, use [`hitl_demo_client.py`](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/clients/hitl_demo_client.py), which prints the request and asks you at the console:

```bash
pip install fastmcp
python hitl_demo_client.py http://localhost:8000/mcp \
    adjust_stock '{"product_id": 1, "delta": 5}'
```

See the [client README](https://github.com/ActianCorp/mcp-server-docs/blob/main/examples/clients/README.md) for the environment variables it accepts, and [Connecting MCP Clients](../../mcp-clients/index.md#elicitation-support-for-write-approval) for which clients support the prompt.