Vaultbeat MCP Server

Overview Schema Source Related Servers Discussions Admin

Menstrual cycle

get_menstrual_cycle

Read-onlyIdempotent

Read recent menstrual cycle data and predict the next period from opted-in Apple Health samples, optionally for a shared partner cycle.

Instructions

Decrypt recent menstrual cycle data locally and predict the next period.

SENSITIVE: menstrual data only reaches this server if the user explicitly opted in on iOS; it stays on-device and is never re-exported. Returns recent samples plus a next-period prediction. Reads YOUR cycle by default; if the cycle being asked about is your partner's, pass partner=true (it reaches this server only if they share it).

Carries a coverage block: quote coverage.days_covered (distinct days, not the row count) and coverage.span_days beside any average or trend. coverage.window_satisfied: false alone does NOT mean a short history: it is also false when older days exist beyond your window. 🔴 Before saying how far back someone's data goes, read coverage.more_available: true means this server can decrypt days OLDER than first_day that your limit left behind — re-read with a larger limit, or quote coverage.oldest_available as the real start of their history. Never report a limit-shaped window as the extent of their data.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`fresh`	No
`limit`	No
`partner`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv0.9.1Oct 3, 2026

addedInput schema / additionalProperties
```
Added value: +false
```

removedInput schema / properties / owner

Removed value: -{
-  "anyOf": [
-    {
-      "type": "string"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null,
-  "title": "Owner"
-}

addedInput schema / properties / partner

Added value: +{
+  "default": false,
+  "title": "Partner",
+  "type": "boolean"
+}

First observedv0.8.1Sep 23, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly/idempotent/non-destructive, but the description adds substantial context they cannot: the opt-in-only, on-device, never-re-exported sensitivity constraint, plus the return shape (samples + next-period prediction). The detailed `coverage` semantics, including the false-negative trap on `window_satisfied` and the `more_available` re-read instruction, is exactly the kind of behavioral disclosure annotations can't convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The purpose is front-loaded, then structured into sensitivity, routing, and coverage-guidance blocks. It is longer than most definitions, but nearly every sentence (opt-in condition, partner routing, window_satisfied caveat, more_available rule) prevents a specific misinterpretation, so the length is largely earned.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values needn't be enumerated, yet the description still tells the agent how to interpret the `coverage` block correctly. Combined with the privacy and partner-routing context, an agent has everything needed to call this tool and report its results without misreading the window.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0%, so the description carries the load, and it does for two of three params: `partner` is explained directly and `limit` is explained through the extended 'limit-shaped window' discussion and the re-read-with-larger-limit instruction. `fresh` is never defined, leaving one undocumented parameter, which keeps this just under full marks.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Decrypt recent menstrual cycle data locally and predict the next period'), so an agent knows exactly what it returns before opening the schema. It is clearly distinguishable from siblings like get_symptoms or get_sleep_nights because it is the only cycle/period tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says the tool reads YOUR cycle by default and to pass `partner=true` when the cycle belongs to a partner. That is real routing guidance for the main ambiguity ('whose data'). It does not, however, describe when to prefer this over adjacent tools such as get_metric or get_symptoms, so it stops short of full when/when-not coverage.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.