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IRAS Tax Assistant

MCP tools

The built-in tools are configurable: enable or disable each one, edit its description, and edit the lookup facts. Your edits apply to the assistant. Below them, your own tools (three examples are preloaded) and how to connect over MCP.

The tools the assistant calls, plus a builder for your own. Three examples are preloaded so you can run one immediately.

  1. Run the built-in lookup with topic GST: the deterministic fact appears, including the SGD 1,000,000 threshold.
  2. Under Your tools, run the example gst_calculator with amount 100: it executes in the server-side QuickJS sandbox and returns the GST and total.
  3. Edit a built-in tool (toggle it, change the description, edit the lookup facts): the config rides along with every chat request, so the assistant honours it.
  4. Build your own with New tool. The Code (sandboxed) kind runs run(input) under a 1 second deadline and 32MB cap with no network or filesystem; paste while(true){} to watch the deadline stop it safely.
  5. Ask the assistant to use your tool by name, then expand the reply's step trace to watch the call.
  6. Connect any MCP client with the config in Connect via MCP at the bottom; the endpoint is /api/mcp.

Built-in

lookup_tax_info

(topic: string)

Facts (keyword to answer)

calculate_tax_estimate

(income: number, deductions: number)

Logic is fixed: chargeable income is income minus deductions, floored at zero.

escalate_to_human

(reason: string, original_query: string)

Logic is fixed: it writes to the advisor queue. See the queue

Your tools

No custom tools yet

Build a keyword lookup, a response template, or a sandboxed code tool. It stays in your browser and the Assistant can call it.

Connect via MCP

These tools are also served over the Model Context Protocol, so any MCP client (Claude Code, the MCP inspector) can call them directly. The Streamable HTTP endpoint is:

https://your-deployment/api/mcp

Add it to a client with this .mcp.json entry:

{
  "mcpServers": {
    "iras-tax": {
      "type": "http",
      "url": "https://your-deployment/api/mcp"
    }
  }
}

lookup and calculate are public (rate limited); escalation requires a bearer token when the server sets MCP_API_KEY.