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Human Design MCP server — 9 tools: charts, cycles, synthesis, transits, chart comparison & a local people roster. For Claude, Cursor, or any MCP client. Powered by Simple Chart Calculator.
Server has 9 well-named tools with complete input schemas and descriptions. Naming follows verb_noun convention (calculate_chart, get_transit, save_person, delete_person, compare_charts). All parameters have type definitions and descriptions. However, output schemas are not documented, responses are raw JSON strings from the API with no shape guidance for LLMs. Error handling is basic (try/catch with message extraction). No tool annotations (readOnlyHint/destructiveHint) despite clear risk levels. Descriptions are adequate (100-200 chars) but lack dependency hints and recovery guidance. The compare_charts tool uses deep gate collection logic that is not exposed to the LLM, limiting transparency.
Calculate a complete Human Design bodygraph chart from birth data. Returns type, authority, profile, incarnation cross, defined/open centers, channels, and every planet as gate.line.color.tone.base for both Personality and Design.
Find the exact moment of a Human Design cycle return (Solar Return, Saturn Return, Uranus Opposition, or Chiron Return) with sub-second precision, and return the full chart for that moment. Uses a binary search on continuous time.
Compare two people's charts and analyze their connection: electromagnetic channels, dominance, compromise, and companionship.
Delete a person from the local roster.
Retrieve a saved person's birth data by name.
Return the interpretive synthesis for a birth chart — type, strategy, authority, signature, not-self theme, profile, definition, incarnation cross and variables. (Same engine as calculate_chart; use this when you want the meaning, not raw planets.)
Output schemas not documented. LLMs cannot plan downstream operations or extract fields without knowing response structure. Responses are raw JSON strings with no shape guidance.
No tool annotations (readOnlyHint, destructiveHint, idempotentHint). Tools like delete_person and save_person have clear risk levels but are not marked, forcing LLMs to infer safety from names alone.
Error handling lacks recovery guidance. Errors return raw API messages (e.g. 'API 401: Invalid key') without actionable next steps. LLMs cannot self-correct or know whether to retry.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | C | 68 | 2026-07-28+ | v2 |
Get the current global Human Design transit chart — the live planetary weather right now.
List everyone saved locally.
Save a person's birth data locally (on this machine) so their chart can be recalled or compared by name later.
compare_charts description does not explain what 'electromagnetic', 'dominance', 'compromise', 'companionship' mean or when to use this tool vs others. Internal gate-collection logic is opaque.
No pagination or result limits documented. list_people and compare_charts could return unbounded results. No guidance on max items or cursor-based pagination.