mailbox-mcp

get_usage

Read-onlyIdempotent

Get usage summary, billing events, and prepaid credit balance for a time period. Returns itemized events (scans, forwards, mail sends) with costs, period totals, and credits.

Instructions

Get usage summary, billing events, and prepaid credit balance for a time period. Returns itemized events (scans, forwards, mail sends) with costs, period totals, and credits. Defaults to the current billing period if no dates are specified. Use this in Cursor/MCP chat when the human asks how many mailbox.bot credits are left; answer with the prepaid balance and explain that only the signed-in human can add funds.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`period_end`	No	End of the reporting period in ISO 8601 format. Defaults to now.
`period_start`	No	Start of the reporting period in ISO 8601 format. Defaults to current billing period start.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes	Usage summary, billing events, and prepaid credit balance.

Schema Changelog

Changes observed during successful MCP inspections.

Changed6 schema fields changedv1.0.3Oct 12, 2026

addedOutput schema / properties / result / additionalProperties
```
Added value: +true
```

changedOutput schema / properties / result / description

Previous value: -"Usage and billing event records."New value: +"Usage summary, billing events, and prepaid credit balance."

removedOutput schema / properties / result / items

Removed value: -{
-  "additionalProperties": true,
-  "description": "One returned record.",
-  "type": "object"
-}

addedOutput schema / properties / result / properties

Added value: +{
+  "credits": {
+    "additionalProperties": false,
+    "description": "Current prepaid credit balance and human top-up URL.",
+    "properties": {
+      "balance_cents": {
+        "description": "Current prepaid credit balance in cents.",
+        "type": "integer"
+      },
+      "balance_display": {
+        "description": "Human-readable prepaid credit balance.",
+        "type": "string"
+      },
+      "billing_url": {
+        "description": "Dashboard URL where the signed-in human can add credits.",
+        "type": "string"
+      },
+      "currency": {
+        "description": "Credit balance currency.",
+        "enum": [
+          "usd"
+        ],
+        "type": "string"
+      }
+    },
+    "required": [
+      "balance_cents",
+      "balance_display",
+      "currency",
+      "billing_url"
+    ],
+    "type": "object"
+  },
+  "events": {
+    "description": "Usage and billing event records.",
+    "items": {
+      "additionalProperties": true,
+      "description": "One returned record.",
+      "type": "object"
+    },
+    "type": "array"
+  },
+  "period": {
+    "additionalProperties": true,
+    "description": "Requested usage period.",
+    "type": "object"
+  },
+  "summary": {
+    "additionalProperties": true,
+    "description": "Usage totals and event-type breakdown for the period.",
+    "type": "object"
+  }
+}

addedOutput schema / properties / result / required

Added value: +[
+  "period",
+  "summary",
+  "credits",
+  "events"
+]

changedOutput schema / properties / result / type
```
Previous value: -"array"New value: +"object"
```

First observedv1.0.0Jun 15, 2026

TDQS

A4.7/5.0

Behavior4/5

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

Annotations already establish read-only, idempotent, and non-destructive behavior. The description adds useful context about return content (billing events, costs, credits) and the default period. It also notes that 'only the signed-in human can add funds,' which provides auth-related context beyond annotations.

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

Conciseness5/5

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

Three concise sentences front-load the main purpose, include key behavioral details, and provide a specific use-case. No filler or redundancy.

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?

The description is complete given its complexity: output schema covers returns, annotations cover safety, and the description covers purpose, defaults, and a concrete usage scenario. Nothing significant is missing.

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 descriptions cover both parameters fully (100% coverage). The description adds value by summarizing the combined default behavior: 'Defaults to the current billing period if no dates are specified,' reinforcing optionality and providing a holistic view of the parameters.

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?

The description clearly states the tool's function: 'Get usage summary, billing events, and prepaid credit balance for a time period.' It specifies output content (itemized events, costs, totals, credits) and is distinct from sibling tools focused on mail, packages, and scans.

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

Usage Guidelines5/5

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

Explicitly tells when to use: 'Use this in Cursor/MCP chat when the human asks how many mailbox.bot credits are left' and even prescribes how to respond. Also explains default behavior when no dates are provided.

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

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