OffWeGoSIM

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the bar is lower, yet the description adds real value by enumerating what does NOT happen: no price reservation, no order creation, no card charge, no eSIM issuance. It omits operational traits an agent might need, such as link expiry or whether the same plan_id always yields the same URL, which is why it is not a 5.

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?

Three short sentences, front-loaded with what is returned and followed by the negative scope. Every clause carries distinct information and nothing is repeated from the name.

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?

No output schema exists, but the description compensates by stating the return is a URL only, which is the key fact for an agent building a downstream step. For a one-parameter tool this is nearly complete; the remaining gap is the absence of guidance on obtaining a valid plan_id and on error behavior for unavailable plans.

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 single parameter plan_id has zero schema description coverage and the description never explains it — no hint that it should come from get_plan/search_plans, no mention of the availability requirement or the pattern constraint. 'One currently available eSIM' is the only indirect signal, which is thin for a tool whose sole input gates everything.

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?

Starts with a specific verb and resource ('Get a link ... to review and buy one currently available eSIM') and immediately delimits the return value ('This only returns a URL'). The scope statement together with the explicit negatives makes it trivially distinguishable from get_plan and search_plans, which retrieve plan data rather than a purchase link.

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 makes the usage context clear (a customer-facing review-and-buy link for a single available eSIM) and rules out side effects, so an agent knows this is the hand-off step before purchase. It never names an alternative sibling or states a when-not condition explicitly, so it falls short of a 5.

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?

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description still adds real behavior not in the annotations: results are limited to 'public' details, and invalid/unavailable/withdrawn IDs produce an error rather than empty data. It does not cover auth requirements or rate limits, so not a 5.

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, zero filler, with the core action and ID provenance front-loaded and the error behavior trailing. Every sentence carries distinct 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?

For a single-parameter read tool with no output schema, the description covers what the tool returns (public plan details), where the input comes from, and the failure mode. The only gap is that with no output schema an agent cannot anticipate which detail fields come back, but that is a minor omission for this complexity level.

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 0%, so the description must carry the load; it does by stating provenance ('returned by search_plans'), which is the key semantic an agent needs for supplying plan_id. Format constraints (pattern, length) are enforced by the schema but not restated, and there is only one parameter, so this is close to fully compensated.

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 ('Read current public details for a plan ID') and scopes it to public/current data. It implicitly separates itself from search_plans by positioning that sibling as the ID source, though it never states the contrast directly (e.g., 'use search_plans to discover, this to fetch one').

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?

It establishes a clear workflow precondition: the plan_id must come from search_plans, which tells an agent when this tool is the right call. It also states the failure condition (unavailable/withdrawn plans error out). No explicit when-not-to-use or alternative fetch mechanisms are given, keeping it at 4 rather than 5.

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?

Annotations already cover read-only, idempotent, non-destructive and open-world behavior, so the description adds meaningful context instead: prices are denominated in USD, no order or payment is created, and country-only results should be preferred over regional bundles. It stops short of describing result size, pagination, or what a plan record contains.

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 with zero padding: the core purpose, the currency, the preference ordering, and the side-effect disclaimer each occupy one clear clause. Front-loaded and easy to scan.

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 five optional filters, no output schema, and no parameter descriptions, the definition leaves the shape of results undefined (fields per plan, ordering, how de-duplication of country vs. regional bundles works). For a read-only search tool this is workable but not complete.

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 0%, so the description must carry parameter meaning. It clarifies the two-letter ISO format for country_code and the USD currency for max_price_usd, but says nothing about limit, min_data_gb, or min_validity_days; it relies on those names being self-explanatory.

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?

"Find prepaid travel eSIM data plans by two-letter ISO destination code" gives a specific verb (find) and resource (eSIM data plans) plus the keying dimension. The closing line "No order or payment is created" implicitly separates it from get_checkout_link, but the distinction from get_plan (search vs. single-plan retrieval) is never made explicit.

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 context is implied by the required destination code, and "Country-only plans are preferred; regional bundles are a fallback" guides result interpretation. However, there is no statement of when to call this versus get_plan or get_checkout_link, and no prerequisites or sequencing guidance.

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