himalaya-mcp

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list_attachments

Retrieves all attachments from a specified email message, downloads them for inspection, and returns each file's name, MIME type, and size for review.

Instructions

List attachments for an email message. Downloads all attachments to inspect them, then returns filename, MIME type (inferred from extension), and size for each.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "id": "<id>"
    },
    "name": "list_attachments"
  }
}

Input Schema

Name	Required	Description
`id`	Yes	Email message ID
`folder`	No	Folder name (default: INBOX)
`account`	No	Account name (uses default if omitted)

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv2.2.2Nov 7, 2026

addedInput schema / properties / id / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "maximum": 9007199254740991,
+    "minimum": 0,
+    "type": "integer"
+  }
+]

removedInput schema / properties / id / type
```
Removed value: -"string"
```

First observedv1.7.0Jun 21, 2026

TDQS

A3.8/5.0

Behavior4/5

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

With no annotations supplied, the description carries the full behavioral burden and does disclose a genuinely non-obvious trait: the tool downloads every attachment internally just to read metadata, which has cost/latency implications. It also flags that MIME type is inferred from the extension, warning about accuracy. It stops short of saying whether the downloaded files are persisted anywhere or what happens with very large attachments.

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?

Two sentences, purpose front-loaded, and the second sentence does real work by describing both the hidden mechanism and the return shape. No filler or redundancy.

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

Completeness4/5

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

For a three-parameter read tool with no output schema, the description covers what the tool does, what it returns, and the cost of calling it. Missing only whether results can be large or paginated, and whether anything is written to disk.

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

Parameters3/5

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

Schema description coverage is 100%, so id, folder, and account are each already documented in the schema. The description adds only the notion that the message ID identifies the target of the listing; it says nothing additional about folder defaults or account resolution. Baseline 3 applies.

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

Purpose4/5

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

States a specific verb and resource ("List attachments for an email message") and enumerates the returned fields (filename, MIME type, size). It never names the sibling download_attachment, so the boundary between listing metadata and saving a file is only implied by the phrase "Downloads all attachments to inspect them."

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

Usage Guidelines3/5

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

Usage is implied rather than stated: the mention of downloading to inspect suggests this is the pre-download survey step, but there is no explicit 'use this before download_attachment' or any exclusion. No prerequisites such as authentication or account selection are addressed.

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