> ## Documentation Index
> Fetch the complete documentation index at: https://docs.symmetry.com/llms.txt
> Use this file to discover all available pages before exploring further.

# STE MCP overview

> Access STE's payroll tax calculation engine through plain English, inside the AI tools you already use — no code, no developer ticket, no payload to assemble.

The Symmetry Tax Engine Model Context Protocol (MCP) server gives you direct access to STE's payroll tax calculation engine through plain English, inside the AI tools you already use. No code. No developer ticket. No payload to assemble.

**Supported clients:** Cursor, Claude Desktop, Claude Code, Gemini CLI, ChatGPT, other AI-enabled IDEs

<Note>
  **ChatGPT is now supported** in addition to MCP clients like Cursor, Claude Desktop, Claude Code, and Gemini CLI.
</Note>

## Who is this for?

* **Tax and compliance analysts**: validating jurisdiction rules and rate changes before they go to production
* **Customer support reps**: answering "why did my paycheck calculate this way?" without waiting on engineering
* **Implementation and onboarding teams**: running parallel-payroll sanity checks during cutover
* **Payroll operations leads**: verifying that an address maps to the correct locals
* **Product managers**: prototyping a new wage-type, benefit, or election before writing a ticket

## Get started

<CardGroup cols={2}>
  <Card title="Install & connect" icon="rocket" href="/ste/ai-interfaces/mcp-installation">
    Add and connect the STE MCP server in Cursor, Claude Code, Gemini CLI, or Claude Desktop.
  </Card>

  <Card title="Claude Desktop walkthrough" icon="play" href="/ste/ai-interfaces/connect-claude-desktop">
    Watch a short demo of connecting Claude Desktop and verifying the connection.
  </Card>

  <Card title="Troubleshooting" icon="wrench" href="/ste/ai-interfaces/mcp-troubleshooting">
    Fix connection failures, redirect errors, missing tools, expired tokens, and 403s.
  </Card>
</CardGroup>

## Available tools

Eleven tools are available. You never need to call them by name—just describe what you need in plain English and the assistant will pick the right one.

| Tool                    | What It Does                                                                                         |
| ----------------------- | ---------------------------------------------------------------------------------------------------- |
| `ste_get_version`       | Returns STE engine version. Use to confirm the connection works.                                     |
| `ste_get_schema`        | Returns the JSON schema for STE requests/responses.                                                  |
| `ste_pay_calc`          | Calculates federal, state, and local payroll taxes for one or more employees.                        |
| `ste_gross_up`          | Given a net amount, computes the required gross and full tax breakdown.                              |
| `ste_jurisdiction_data` | Filing-status options, allowance rules, and parameters for a given tax ID and pay date.              |
| `ste_location_code`     | Resolves an address or coordinates to STE GEO/location code, PSD, school district, and municipality. |
| `ste_location_tax`      | All applicable taxes (federal through local) for a `taxReferenceFull` and effective date.            |
| `ste_tax_id_list`       | Wildcard search over STE's reference catalogue of tax IDs, filterable by pay date and status.        |
| `ste_set_tax_list`      | Returns the tax codes and parameters already applied to an employee setup.                           |
| `ste_benefit_info`      | IRS/state benefit codes, tax treatment, combined limits, and catch-up amounts.                       |
| `ste_benefit_status`    | Active benefits, YTD usage, and effective contribution limits for a setup.                           |

## Sample prompts

Copy these directly into your AI assistant once connected.

### Compliance analyst: validating a rate change

> For pay date 2026-05-15, what taxes apply to location 42-003-1213644 (Pittsburgh, Allegheny)? I'm specifically looking for the Local Services Tax and EIT rate so I can verify our internal table.

### Customer support: debugging a wrong-number ticket

> A client is reporting that the Ohio SUTA 2025 wage base isn't capping at \$9,000. Here's the payload from their ticket. Please replay it through STE and walk me through where the cap should have applied.

### Implementation lead: sanity-checking onboarding

> Look up location codes for these three addresses \[paste]. For each, list the local taxes a new employee would face and tell me which ones the employee can opt out of versus which are mandatory.

### Product manager: prototyping a feature

> Run the same \$3,000 regular wage in PA, NY, and CA semi-monthly, single, 1 exemption. Show me the federal + state + local totals side by side so I can design the UI for our multi-state preview.

### Tax operations: end-of-quarter parity check

> For this employee with \$87,500 YTD in PA and a \$5,000 bonus paid 2026-06-30, calculate Supplemental flat method and compare to combined-aggregation. I want to see the FICA + PA SIT + local difference.