Yahoo Mail MCP Server

create_draft

Save a new email draft to your Yahoo Mail Drafts folder without sending it, so you can review, edit, and send it later from Yahoo Mail.

Instructions

Create a new email draft and save it to the Yahoo Mail Drafts folder. The email is NOT sent; the user reviews and sends it from Yahoo Mail. Returns the full draft and its UID. To revise the draft later, call update_draft with that UID.

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": {
      "to": "<to>",
      "subject": "<subject>",
      "body": "<body>"
    },
    "name": "create_draft"
  }
}

Input Schema

Name	Required	Description
`cc`	No	Optional Cc address(es)
`to`	Yes	Recipient address(es), e.g. ["Jane <jane@example.com>", "b@example.com"]
`bcc`	No	Optional Bcc address(es)
`body`	Yes	Plain-text body of the email
`html`	No	Optional HTML version of the body. If omitted, the email is plain text only.
`subject`	Yes	Subject line
`attachments`	No	Optional paths of local files to attach (e.g. files saved by download_attachments)

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?

With no annotations, the description carries the full burden and does well: it discloses that the email is NOT sent and is only saved for user review, which is the critical safety-relevant behavior, and it reports the return payload ('full draft and its UID'). It omits permission/auth requirements and how invalid attachment paths are handled.

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 tightly written sentences; the core action, the non-send guarantee, and the follow-up routing are all front-loaded with zero filler.

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 7-parameter creation tool with no output schema, the description covers what an agent most needs: what is created, that nothing is sent, what is returned, and how to continue editing. Only auth/permission context and edge-case attachment handling are absent.

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 schema fully documents to/cc/bcc/subject/body/html/attachments. The description adds no parameter-level meaning (e.g. format expectations for the recipients array), so the 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 ('Create a new email draft') plus the destination ('Yahoo Mail Drafts folder'), which is unambiguous. It differentiates itself from update_draft explicitly, though it never distinguishes itself from the sibling create_reply_draft, so sibling differentiation is only partial.

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?

Names the follow-up alternative and the condition that selects it: 'To revise the draft later, call update_draft with that UID.' It also clarifies the non-sending workflow, telling the agent the user sends manually. It does not state when a draft is preferable to a reply draft or other creation paths.

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

Deploy Server