e-eSIM Catalog

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

Annotations already declare this as a safe, open-world, non-destructive read, so the safety profile is covered. The description adds a list of the retrieved fields (throttle behaviour, daily reset, coverage list, reviews), which is useful scope information beyond the annotations, but it discloses nothing about latency, pagination, or failure modes.

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?

Single front-loaded sentence that names the resource first and then quantifies the returned fields with no filler. Slightly dense as one continuous clause list, but every phrase carries 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?

With an output schema present, the description need not explain return values, and annotations cover the safety profile; the schema documents both parameters fully. What remains is the workflow tie to search_esim_plans, which is only implied, leaving a small gap.

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 both parameters are already fully documented, including the language localisation effect on names and link currency. The description only references product id and adds no syntax, format, or edge-case meaning beyond the schema, matching the baseline for high-coverage schemas.

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 ('Full details for one e-eSIM plan by product id') and enumerates exactly what is returned, so an agent knows it is a single-record fetch. However, it never names or contrasts itself with the sibling search_esim_plans, which is the closest alternative, so sibling differentiation is only implicit.

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 product id hint ('WooCommerce product id from search_esim_plans') implies the tool follows a search step, giving implied usage. There is no explicit when-to-use statement, no exclusions, and no direct comparison against search_esim_plans or start_checkout.

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 readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered structurally. The description adds that results include full specs, prices and a direct link, but discloses nothing about pagination, result limits, or behavior for unknown destinations, so it adds only modest value.

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: purpose, return content, and usage trigger, with the primary resource stated first. Nothing is filler, despite the minor awkwardness of the "e-eSIM travel eSIM" phrasing.

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?

An output schema exists, so return-value detail is unnecessary here, and the annotations cover the safety profile. The remaining gap is sibling disambiguation within a three-tool family where responsibilities are only implied.

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 all four parameters (including the enum values and the currency/language handling) are already documented in the schema. The description restates the destination concept (country or region) but adds no syntax or constraint beyond that, matching the baseline for a fully covered 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 names a specific verb and resource ("Find eSIM travel eSIM plans for a destination") and states the return content (specs, prices, direct link). It does not, however, distinguish itself from siblings get_plan_details or start_checkout, leaving overlap between "full specifications" and a details tool.

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?

"Use when a user wants mobile data abroad" gives a clear, actionable usage trigger. There is no when-not guidance and no routing to siblings (e.g., when to call get_plan_details instead), so it stops 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?

Adds behavior beyond the annotations: no account required, the eSIM is emailed after payment, and there is no in-chat order tracking or discount field. The readOnlyHint=true is consistent here because the purchase itself occurs on an external page, not in the chat session.

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 the core action and keeps to three tight sentences. The payment-method parenthetical is mildly extraneous but still informative rather than filler.

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?

Covers prerequisites (no account), post-payment behavior (eSIM emailed), and limitations, which is what an agent needs for a handoff tool. Return-value description partially duplicates the existing output schema, so it is slightly redundant.

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% and both parameters (product_id, language) are documented in the schema, including the language/currency effect. The description adds no parameter-level detail beyond the schema, so the 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 outcome — hand the customer to the e-eSIM shop to buy one plan and return a buy_url. It is plainly distinguishable from get_plan_details and search_esim_plans, which do not hand off to payment.

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?

Gives usable context (buy one plan, no account needed) and negative constraints (no in-chat order tracking, no discount-code field) that prevent misuse. It stops short of explicitly naming when to prefer this over the sibling plan-lookup tools, leaving that sequencing to inference.

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