This documentation describes a mock MCP server. It does not file with the IRS and does not connect to any IRS system.

Docs

Guides

• Quickstart: Build the mock server, register it with an MCP client and make the first calls.
• Tools reference: Inputs, outputs and example responses for each mock MCP tool.
• Error catalog: Every rejection and warning code the mock emits, with its basis and fix.
• Agent playbook: Calling sequence, retries, human checkpoints and the never-do list for AI agents.

Form references

• Forms index: Which forms the mock models and which are unavailable.
• Form 941: Fields, computed values and validation for the mock Form 941 and 941-X.
• Form 944: Fields, computed values and validation for the mock Form 944.
• Form 7004: Fields, extension rules and validation for the mock business extension Form 7004.