SolMail MCP

send_mail

Send physical letters using Solana cryptocurrency. Compose content, specify recipient address, and submit for printing and mailing through SolMail MCP.

Instructions

Send physical mail using Solana cryptocurrency. Composes a letter, creates a Solana payment transaction, and submits to SolMail for printing and mailing. Requires wallet configuration.

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": {
      "content": "<content>",
      "recipient": "<recipient>"
    },
    "name": "send_mail"
  }
}

Input Schema

Name	Required	Description
`content`	Yes	The letter content (plain text, will be formatted as a letter)
`recipient`	Yes	Recipient address information
`mailOptions`	No	Mail formatting options

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.1.0Feb 23, 2026

TDQS

A3.8/5.0

Behavior3/5

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

With no annotations provided, the description carries the full burden. It discloses key behavioral traits: it's a write operation ('Send physical mail'), involves payment ('creates a Solana payment transaction'), and external processing ('submits to SolMail for printing and mailing'). However, it lacks details on costs, delivery times, error handling, or confirmation mechanisms that would be helpful for an agent.

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

Conciseness4/5

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

The description is appropriately sized (two sentences) and front-loaded with the core purpose. Every sentence earns its place by explaining the process and prerequisite. Minor improvement could come from slightly more structured phrasing, but it's efficient.

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

Completeness3/5

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

Given the tool's complexity (involving cryptocurrency, physical mail, and external services), no annotations, and no output schema, the description is moderately complete. It covers the high-level workflow and prerequisite but lacks details on costs, success/failure responses, or integration specifics that would help an agent fully understand the operation.

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 all parameters. The description adds no additional parameter semantics beyond what's in the schema (e.g., it doesn't explain content length limits, address validation, or mailOptions implications). Baseline 3 is appropriate when the schema does all the work.

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 specific action ('Send physical mail'), resource ('using Solana cryptocurrency'), and process ('composes a letter, creates a Solana payment transaction, and submits to SolMail for printing and mailing'). It distinguishes from sibling tools like get_mail_quote (which only quotes) and wallet-related tools by focusing on the complete sending operation.

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 explicitly states 'Requires wallet configuration,' providing clear context for when to use this tool (when wallet is set up). However, it doesn't specify when to use alternatives like get_mail_quote (for cost estimation before sending) or when not to use this tool (e.g., for digital communication).

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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