Yahoo Mail MCP Server

search_emails

Find Yahoo Mail messages by subject, sender, date range, folder, or unread status; returns permanent UIDs for follow-up actions.

Instructions

Search emails using UIDs with advanced filters. Returns UIDs which are permanent identifiers that don't change when emails are deleted. Get UIDs from results for subsequent operations.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

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

Input Schema

Name	Required	Description	Default
`count`	No	Number of results to return (default: 10, max: 50)
`query`	No	Search term for subject or sender (can be empty for date-only searches)
`dateTo`	No	Filter emails up to this date (ISO 8601 or RFC 2822 format)
`folder`	No	Folder to search in (default: INBOX). Use list_folders to see available folders.	INBOX
`sender`	No	Filter by specific sender email address or name
`dateFrom`	No	Filter emails from this date onwards (ISO 8601 or RFC 2822 format)
`unreadOnly`	No	Only return unread emails (default: false)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv3.1.0Sep 28, 2026

TDQS

A4/5.0

Behavior4/5

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

No annotations exist, so the description carries the burden. It adds useful non-obvious behavior: UIDs are permanent and do not change when emails are deleted, which helps agents trust them for future calls. It does not explicitly state read-only status, though 'Search' implies it.

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 sentences, all contributing value: the purpose is front-loaded, the UID permanence note is meaningful, and the chaining guidance is actionable. 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?

With no output schema, the description adequately explains the return value (UIDs) and how to use it. It covers the important chaining behavior and leaves parameter specifics to the highly detailed schema, making it sufficiently complete for correct invocation.

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 coverage is 100% with detailed parameter descriptions, so the baseline is 3. The description adds no parameter-level meaning beyond the generic 'advanced filters' phrase, which does not enhance the schema.

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?

The description clearly states the tool searches emails with advanced filters and returns UIDs, which are stable identifiers. It distinguishes itself via the focus on UIDs for downstream operations, but does not explicitly contrast with sibling tools like list_emails, and the phrase 'using UIDs' is slightly awkward.

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?

The description tells agents to use this tool when they need UIDs for subsequent operations, providing a clear context. It does not explicitly state when to prefer list_emails or exclude alternatives, so it stops short of a 5.

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

Deploy Server