International calls from your AI agent: price per minute and a Call link to the browser dialer.
Scored across 2 tools
The two tools have clearly distinct purposes: get_call_price targets a specific phone number, while get_country_call_prices targets a country without a number. The descriptions explicitly state when to use each, so an agent can easily select the right one.
Both tools follow a consistent get_ + noun phrase pattern in snake_case. The minor difference in plurality (price vs prices) is logical and does not break the predictable convention.
With only 2 tools, the set is borderline thin for the stated purpose of international call pricing and dialer links. Both tools earn their place, but a typical well-scoped set would have a few more operations.
The surface covers the core workflows: pricing and a dialer link for a specific number, and pricing and a dialer link for a country. Ancillary operations like listing supported countries or managing account details are missing, but agents can work around these gaps for basic calls.
Helps the person call a phone number anywhere in the world with Suparelay: returns the price per minute and a Call link that opens the Suparelay browser dialer with the number ready. Use it when the person wants to call a phone number or asks what a call to it costs. Pass the number in E.164 format with the country code, such as +33142868200. The person talks on the call in the browser; this tool does not dial.
| Name | Required | Description | Default |
|---|---|---|---|
| number | Yes | The phone number in E.164 format, such as +33142868200 |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior. The description adds useful context: it returns a Call link and the person talks in the browser, and crucially 'this tool does not dial.' It does not cover pricing source or currency, but those are not strictly required.
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?
Front-loads what the tool returns and when to use it, then gives parameter format, then a key behavioral caveat. Sentences are purposeful, though the E.164 detail duplicates the schema.
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?
With no output schema, the description explains the return values (price per minute and Call link) and the non-dialing behavior. It is sufficient for calling correctly, though it does not differentiate from the sibling country-price 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% and the single parameter already includes E.164 format and an example. The description repeats the same E.164 format instruction and example, adding no semantics beyond the schema.
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?
States a specific verb and resource: returns price per minute and a Call link for a phone number. It clearly describes the output and that it does not dial, but does not explicitly distinguish itself from the sibling get_country_call_prices.
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?
Provides clear when-to-use guidance: 'Use it when the person wants to call a phone number or asks what a call to it costs.' It does not mention alternatives or exclusions, such as when to use the sibling country-level tool instead.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Helps the person call a country with Suparelay: returns the landline and mobile prices per minute and a Call link that opens the Suparelay browser dialer. Use it when the person wants to call a country or asks what calls to it cost, without a phone number. Pass the two-letter ISO country code, such as IN. The person talks on the call in the browser; this tool does not dial.
| Name | Required | Description | Default |
|---|---|---|---|
| country | Yes | The two-letter ISO 3166-1 country code, such as IN |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, non-destructive, and closed-world. The description adds genuinely new behavior: the return includes a Call link opening the Suparelay browser dialer and that this tool 'does not dial' — an important scope limit not derivable from annotations.
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?
Four short sentences, front-loaded with what is returned and followed by usage and a scope caveat. Every sentence carries information, though the closing browser-dialer remark slightly overlaps the earlier 'Call link' sentence.
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?
With no output schema, the description compensates by explaining the return payload (landline/mobile prices per minute and a Call link) and clarifying that the tool itself does not place the call. An agent has everything needed to invoke and interpret it.
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?
One parameter with 100% schema description coverage, so the schema already documents the ISO 3166-1 two-letter code and its example. The description repeats the format guidance ('two-letter ISO country code, such as IN') without adding anything new, so baseline 3 applies.
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?
States a specific verb and resource: returns landline and mobile per-minute prices plus a Call link for a given country. The clause 'without a phone number' functionally separates it from the sibling get_call_price, which presumably takes a number, though the sibling is not named.
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?
Explicitly says when to use it: 'when the person wants to call a country or asks what calls to it cost, without a phone number.' This is a clear usage condition, but it does not name the alternative tool or state when to prefer get_call_price instead.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
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