mcp-server-smallinvoice

send_offer_by_email

Email a specific offer to designated recipients. Requires offer ID, subject, body, and recipients. Optionally specify sender. Irreversible.

Instructions

Sends specified offer by email (SENDS REAL EMAIL — irreversible)

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": {
      "offer_id": "<offer_id>",
      "subject": "<subject>",
      "body": "<body>",
      "recipients": "<recipients>"
    },
    "name": "send_offer_by_email"
  }
}

Input Schema

Name	Required	Description
`offer_id`	Yes	offer ID
`subject`	Yes	email's subject
`body`	Yes	email's body
`recipients`	Yes	email's recipients
`from`	No	sender's email: if nothing specified, company's default will be applied; possible values: CO - company's email, U - user's email, S - company's SMTP email, CE - central email: no-reply@smallinvoice.com

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0May 29, 2026

TDQS

A3.7/5.0

Behavior4/5

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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the description adds value by explicitly stating 'SENDS REAL EMAIL — irreversible'. This warns the agent that the action has real-world consequences and cannot be undone, which is useful behavioral context beyond annotations.

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?

The description is a single sentence that packs essential information: action, resource, and critical warning. No unnecessary words. Front-loaded with the core function.

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 has 5 parameters (4 required) and no output schema, the description is minimal. It doesn't describe return values, error states, or side effects beyond irreversibility. Adequate but not comprehensive for a potentially impactful action.

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%, so parameters are documented. The description does not add any additional meaning or constraints beyond the schema. For example, it doesn't explain the 'recipients' array format or the allowed values for 'from'. Baseline 3 is appropriate.

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 what the tool does: 'Sends specified offer by email'. It distinguishes itself from send_offer_by_post by implying this is for email, and the irreversibility note adds clarity. The verb 'sends' and resource 'offer' are specific.

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

Usage Guidelines2/5

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

No explicit guidance on when to use this tool vs alternatives like send_offer_by_post. The description only mentions irreversibility but does not specify prerequisites, context, or scenarios where email is appropriate. Lack of 'when-to-use' or 'when-not-to-use' reduces score.

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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