Roamzo Travel eSIMs

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

Annotations already establish read-only, idempotent, open-world, and non-destructive behavior. The description adds meaningful behavioral context beyond that: only verified public retail offers are ranked, unverified prices remain unknown, rankings apply only to verified exact matches in pricePosition, and alternatives are separately labeled.

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 and front-loaded: it starts with the comparison action and scope, then explains outputs and verification limitations. Every sentence contributes useful information without repetition.

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 relatively complex 9-parameter comparison tool with no output schema, the description does well on return content and verification caveats. However, it leaves several parameters and usage alternatives unexplained, so it is only partially complete for correct invocation.

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 very low at 11%, so the description carries a heavy burden. It mentions country, trip duration, data preference, and currency, but omits meaningful explanation for providers, quantity, locale, unlimited, and includeTechnicalDetails.

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 states a specific verb and resource: compare verified public retail travel eSIM offers, scoped by country, trip duration, data preference, and currency. It is clear enough to distinguish this from plan-listing or retrieval siblings, but it does not explicitly name those alternatives.

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 when to use the tool by describing the comparison inputs, but it gives no explicit when-not guidance or named alternatives such as get_esim_plan or search_esim_destinations. The caveat about verified exact matches helps, but routing guidance remains implicit.

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, idempotentHint and destructiveHint=false, so safety is covered. The description adds genuine context beyond that: that Unlimited is a total allowance rather than a guarantee of full speed, and that the phone must be unlocked and eSIM-capable. Those are useful caveats, though the framing is repetitive and partly self-contradictory in tone.

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 core action is front-loaded correctly, but the body repeats 'Unlimited' three times in different phrasings ('storefront data label: Unlimited', 'total dailyAllowance is Unlimited', 'Unlimited is the total data allowance'), which is confusing rather than clarifying. Several sentences do not earn their place.

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?

There is no output schema, so the description should indicate what comes back; it only gestures at fields (dailyAllowance, fairUsagePolicyUrl) without structure. With four of five parameters undocumented in the schema, the description leaves an agent guessing on the required planId format and the currency/locale effect.

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 only 20% (only 'days' is documented), so the description must compensate. It does explain includeTechnicalDetails semantics well, one of five params, but leaves planId format, currency and locale unexplained, so it only partly closes the gap.

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 opening sentence gives a clear verb and resource: read a selected plan and its coverage. It is distinguishable from siblings like list_esim_plans and compare_esim_prices. However, the purpose is muddied by the repeated and confusing 'Unlimited' statements that read more like marketing copy than a scope statement.

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 does give conditional guidance for includeTechnicalDetails (false for shopping, true for activation or network questions) and routes fair-usage questions to fairUsagePolicyUrl. But it never names a sibling tool or explains when to call this instead of list_esim_plans or compare_esim_prices.

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 mark the tool as read-only and idempotent. The description adds useful semantics: upgrades replace the plan rather than adding to it, and more high-speed data does not mean faster network speed. It does not describe the return shape, and there is no output schema.

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, with the purpose stated first. Each 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?

It covers purpose and the key semantics of what an upgrade means. It lacks documentation of the return contents and of the planId source, which matters because there is no output schema and parameter coverage is low.

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 25%, and only 'days' has a description. The description never explains planId (where it comes from), currency format, or locale. 'Selected plan' gives weak indirect meaning to planId, which does not make up for the coverage gap.

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?

It names a specific action and resource: finding verified data and extra-coverage upgrades for a selected plan. 'For the selected plan' implies it follows get_esim_plan or list_esim_plans, but it doesn't explicitly set itself apart from siblings such as compare_esim_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?

Context is implied: use it after a plan is selected. It adds presentation guidance ('Show only available upgrades and the added countries'). There is no explicit when-not-to-use guidance and no pointer to siblings for the prerequisite planId.

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 safety profile is clear. The description adds useful context beyond annotations: it states that the tool returns current public offers, plan details, coverage, pagination, and notes that fixed bundles retain actual validity. This is meaningful extra behavioral information.

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 two front-loaded sentences with little waste. It states the main listing inputs first and the return behavior second. The phrase about fixed bundle validity is slightly cryptic but still relevant and compact.

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 nine parameters, low schema description coverage, and no output schema, the description is not complete enough. It explains the high-level return content but omits guidance on several optional parameters, especially the alternatives-related ones that likely matter for comparison workflows.

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 very low (11%), so the description must compensate. It covers destination, duration, currency, and data preference at a high level, but leaves several parameters unexplained, including locale, limit, offset, includeAlternatives, and alternativesForPlanId. Pagination is mentioned only as a return feature, not as a parameter behavior.

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 a specific verb and resource: list Roamzo travel eSIM plans. It also names the main scoping inputs (destination, duration, data preference, currency), so an agent can understand the tool's role. However, it does not explicitly distinguish this listing tool from siblings such as compare_esim_prices or 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 gives no explicit guidance on when to use this tool versus alternatives like compare_esim_prices or get_esim_plan. It describes the listing behavior and inputs but leaves the agent to infer when this tool is the right choice.

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 safety is covered. The description adds useful behavioral context beyond that: it discloses the result shape ('the preferred unlimited offer or a few fixed bundles') and warns against inferring coverage from region names, which is a real matching-behavior caveat.

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, zero padding, with the core matching behavior front-loaded before the prerequisite and the exclusion. Every sentence carries actionable 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 7-parameter tool with 14% schema coverage and no output schema, the description is adequate but leaves gaps: it doesn't explain locale, minDataGb, or what happens when unlimited defaults to true and the bundles returned are fixed-data. The return shape is described only in loose qualitative terms.

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 only 14% (only 'days' is documented), so the description must compensate and does so partially: it explains that countryCodes must cover every requested country, that days/quantity/currency drive the result, and implicitly ties 'unlimited' to preferring unlimited offers. Undocumented are locale, minDataGb semantics, and the effect of unlimited's default of true versus fixed bundles.

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?

Uses a specific verb ('find') on a specific resource (unlimited offer or fixed bundles) and states the matching dimensions: all requested countries, duration, phone quantity, and payment currency. It is clearly distinguishable from siblings like list_esim_plans and compare_esim_prices because it describes a multi-constraint matching operation rather than a listing or price comparison.

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 routes the agent to search_esim_destinations as a prerequisite step ('resolve cities to country codes first') and adds a concrete exclusion ('Do not infer coverage from a region name'). It does not explain when to prefer this tool over compare_esim_prices or get_esim_upgrades, so it falls short of full when/when-not coverage.

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 adds that results are 'live' and that regional coverage varies by plan, but says nothing about result count, pagination behavior, or empty-result handling beyond what limit/offset imply.

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 the core action and zero filler. Minor deduction: the example 'popular islands such as Brussels and Bali' is factually sloppy (Brussels is not an island), which slightly muddies the query-format guidance.

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 zero-required-param search tool with no output schema, the description should at least say what comes back and whether results are paginated. It covers input vocabulary and coverage nuance but leaves the returned entity and paging story to inference.

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 explains the accepted query forms well (country names, ISO codes, cities, islands) but leaves limit, offset and the 40-value locale enum completely undiscussed.

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 ('search live country and regional coverage') that an agent can distinguish from the plan/pricing siblings. It is clear what is being looked up, though it never says what a result actually is (a destination, a plan, a price).

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 only implied: you search coverage before acting on plans/prices. The line 'Regional coverage is specific to each plan' hints that plan-level detail belongs to get_esim_plan or list_esim_plans, but no alternative is named and no when-not condition is given.

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