compare_esim_providersHow travel eSIM providers stand against each other on eSIMCompare's data: plans and destinations covered, entry price, best price per GB, share of unlimited plans, an independent verdict, and links to the full review and head-to-head pages. Pass one to four providers, or none for all of them.
| Name | Required | Description | Default |
|---|---|---|---|
| providers | No | Provider names, such as ['Airalo', 'Holafly']. Omit for every provider. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare this as read-only, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds valuable behavioral context by listing what the comparison returns: plans, destinations, pricing metrics, unlimited-plan share, verdict, and review links.
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 definition is two efficient sentences with no filler. It front-loads the comparison purpose and then states the provider-passing rule directly.
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 simple read-only comparison tool with one optional parameter and no output schema, the description provides enough detail about both the comparison dimensions and the returned information. Nothing critical is missing for an agent to select and call it correctly.
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 coverage is 100%, so the single providers parameter is already well documented, including examples and omission behavior. The description adds cardinality and default behavior (one to four, or none for all), but mostly restates what the schema provides.
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 clearly frames the tool as a provider-vs-provider comparison and enumerates the dimensions compared, so the resource and operation are understandable. It does not explicitly contrast itself with siblings like search_esim_plans or esim_price_index, which keeps it from a 5.
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?
Usage is implied by the comparison framing, and the description gives practical input guidance: pass one to four providers or none at all. However, it does not state when to choose this tool over the sibling search or price-index tools, or when not to use it.
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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