Yahoo Mail MCP Server

download_attachments

Save email attachments from a Yahoo Mail message by UID to disk. Returns saved file paths; use read_email to find attachment names first.

Instructions

Download attachments from an email (by UID) and save them to disk. Returns the saved file paths. Use read_email to see attachment names first.

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": {
      "uid": "<uid>"
    },
    "name": "download_attachments"
  }
}

Input Schema

Name	Required	Description	Default
`uid`	Yes	UID of the email containing the attachments
`folder`	No	Folder containing the email (default: INBOX)	INBOX
`saveDir`	No	Directory to save attachments to (default: ~/Downloads/yahoo-attachments)
`filenames`	No	Only download attachments with these filenames (default: all attachments)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv3.1.0Sep 28, 2026

TDQS

A4/5.0

Behavior3/5

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

No annotations are provided, so the description must carry behavioral context. It discloses the disk-writing side effect and that it returns saved file paths, but it does not cover permissions, overwrite behavior, directory creation, or error handling for missing 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?

Three short sentences are front-loaded with the core action, then the return behavior, then the prerequisite workflow. There is no wasted wording.

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?

The tool is simple and the schema fully documents all four parameters. The description covers the core action, return value, and a useful prerequisite. It could be slightly richer about filesystem behavior, but it is complete enough for an agent to call correctly.

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 the parameters are already well documented. The description adds little beyond the schema for uid, folder, saveDir, and filenames, though it does imply the uid identifies the target email and that filenames can be discovered via read_email.

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 uses a specific verb and resource: 'Download attachments from an email (by UID) and save them to disk.' It also identifies the relevant sibling, read_email, which helps an agent distinguish this tool from email-reading tools.

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?

It gives explicit workflow guidance: 'Use read_email to see attachment names first.' This tells the agent when to reach for read_email before calling this tool, though it does not state exclusions or alternative download tools.

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

Deploy Server