Siima eSIM

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

No annotations provided, so description carries full burden. It discloses Stripe-powered but hosted on their site, no account needed, email delivery within a minute post-payment. Fully explains what happens beyond the API call.

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?

Two sentences, no filler. First sentence states core function, second explains optional behavior. Front-loaded and efficient.

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 3 params, no output schema, and no annotations, the description covers purpose, return value (URL), payment flow, email delivery, and optional parameters. Agent has sufficient context to invoke 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 baseline is 3. Description adds value by explaining optional email behavior (pre-fills payment page vs collects first) and references search_esim_plans for plan_id. Provides context beyond 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?

Clearly states it creates a secure payment link on siima.io for an eSIM plan. Distinguishes from sibling tools (get_esim_plan, list_destinations, search_esim_plans) which are query/lookup tools.

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 tells to give the returned URL to the user for payment and optionally pre-fill email. Does not explicitly state when not to use, but the tool's unique purpose makes usage clear without exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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

No annotations provided, so description carries full burden. It implies read-only behavior ('fetch') and mentions no destructive actions. However, it does not disclose what happens on missing plan_id or rate limits. Still adequate for a simple fetch tool.

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?

Two sentences, no filler. First sentence states core purpose; second sentence provides crucial workflow. Front-loaded and efficient.

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?

Description covers purpose and usage flow well. However, without an output schema, it does not hint at the structure of returned details (e.g., fields like price, coverage). For a simple fetch tool, nearly complete but missing output shape.

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% with descriptions for both parameters. Description adds context by linking plan_id to search_esim_plans and notes currency default. This extra guidance justifies a score above baseline 3.

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?

Clearly states 'Fetch full details of a single Siima eSIM plan by its id', using a specific verb and resource. Distinguishes from siblings by referencing search_esim_plans for the id and create_checkout_link for purchase.

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 tells when to use (after search, to get full details) and gives a complete workflow: call create_checkout_link with plan id, provide URL to user, and explains automatic email delivery after payment. Guides agent on tool selection versus siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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

No annotations are provided, so the description must disclose behaviors. It details output: countries, plan counts, cheapest price, and country code format. However, it does not mention pagination, ordering, or potential caching. For a simple list, this is mostly adequate.

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?

Two concise sentences, no redundant information. The description is front-loaded with the action and resource, providing essential details efficiently.

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?

Given the tool's simplicity (one optional parameter, no output schema), the description fully covers what the tool does and what it returns. It explains the output fields and the country code standard, making it complete for an agent to use.

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% for the single parameter (currency) with a clear description in the schema. The tool description does not add additional meaning beyond the schema, so baseline 3 is appropriate.

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 states the tool lists all countries with eSIM plans, including plan counts and cheapest total price, and specifies the country code standard (ISO alpha-2). This distinguishes it from sibling tools like search_esim_plans and get_esim_plan.

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 implies usage for browsing available destinations, but does not provide explicit guidance on when to use this tool versus alternatives like search_esim_plans or create_checkout_link. No exclusions or context are given.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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

With no annotations, the description carries the full burden. It discloses that the price is final (all fees included), the currency must be specified, and eSIM is emailed automatically without needing an account. It lacks details on pagination, data freshness, or result structure, but these are acceptable given the tool's scope.

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 description is compact with three sentences: first lists search criteria, second explains price, third covers purchase flow. It is front-loaded, efficient, and contains no irrelevant information.

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?

Given 7 parameters, no output schema, and no annotations, the description covers the search purpose, price details, and purchase workflow. It implies the output includes plan IDs and a list. Minor improvements could include a brief note on output format or error conditions.

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?

The schema already covers all parameters with descriptions (100% coverage). The description adds value by explaining that max_price corresponds to the final checkout total and providing examples for country codes. This enhances understanding 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?

The description clearly states the verb 'search' and the resource 'prepaid travel eSIM data plans', and lists specific filtering criteria (country, region, data, price, duration). It effectively distinguishes from siblings like create_checkout_link and get_esim_plan by focusing on searching rather than buying or retrieving a single plan.

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 explicitly explains when to use this tool for finding plans and then directs to create_checkout_link for purchase. It also clarifies the price and post-payment flow. However, it does not mention alternatives like get_esim_plan for direct plan lookups, which could improve guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.