Human Design API Overview

Overview

The HumanDesign.ai API ships in three surfaces that share the same membership billing system:

Legacy REST for direct endpoint integrations.
Agent HTTP at https://api.humandesign.ai/agent/v1/tools/* for action clients.
MCP at https://mcp.humandesign.ai/ for tool-based AI workflows.

All three surfaces use the same API key and the same monthly PMPro quota.

Legacy REST supports X-Api-Key headers and the api_key query parameter. Agent HTTP and MCP require header authentication only:

X-Api-Key: your_api_key_here
Authorization: Bearer your_api_key_here

Query-string API keys are rejected on /agent/v1 and the dedicated MCP transport.

Tier	REST Access	Agent / MCP Access
Creator	Core charts, composites, library, locations	`resolve_timezone`, `generate_chart` (core), `generate_composite_chart`, `get_reference_item`
Startup	Creator + enhanced charts, transits, return charts	Creator tools + `generate_chart` (full) and `get_transits`
Business	Startup + calendar, celebrity, webhooks, stream, batch	Startup tools + `search_celebrities`
Enterprise	Full Business access in v1	Full Business access in v1

Each successful legacy REST request consumes 1 API unit.
Each authorized Agent HTTP or MCP execution attempt consumes 1 API unit when it reaches the calculation provider.
Invalid arguments, unknown references, and unsupported detail levels consume zero units.
MCP initialize, notifications/initialized, ping, and tools/list are checked for entitlement but do not consume usage.