Get EnvoiSMS pricing. Pass to (a phone number in E.164, e.g. +2348012345678) for that destination's per-SMS rate; omit it for Moroccan rates and credit packs. Public — no authentication required.
| Name | Required | Description | Default |
|---|---|---|---|
| to | No | Destination phone number in E.164 format, e.g. +2348012345678. Optional. |
Changes observed during successful MCP inspections.
Input schema / properties / toAdded value: +{
+ "description": "Destination phone number in E.164 format, e.g. +2348012345678. Optional.",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden. It explicitly states 'Public — no authentication required,' which is a key behavioral trait. It also explains the conditional behavior based on the `to` parameter, though it does not discuss output format, potential errors, or rate limits.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The entire description is two sentences with no filler. The core purpose is front-loaded, parameter usage is explained with an example, and the authentication requirement is a single concise suffix. Every sentence earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with a single optional parameter and no output schema, the description covers everything needed to invoke it correctly: parameter format, conditional behavior, and authentication requirements. There are no significant gaps for a pricing lookup tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the baseline is 3. The description adds meaningful semantics beyond the schema by explaining the exact effect of including or omitting `to` and providing an E.164 example. This clarifies the parameter's purpose in a way the schema alone does not.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description opens with a specific verb and resource: 'Get EnvoiSMS pricing.' It clearly distinguishes this tool from siblings by focusing exclusively on pricing, and it explains the two modes of operation (destination-specific vs. Moroccan rates), leaving no ambiguity about what the tool does.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear context for when to pass `to` versus when to omit it, effectively acting as usage guidance. It does not explicitly name alternatives or state when not to use the tool, but since no sibling tool handles pricing, the context is sufficient.
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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