Lithuania Payments (Stripe — cards / Apple Pay)

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

The description adds value beyond annotations by detailing the default deferred cancellation vs immediate option, and notes fairness to the buyer. Annotations already indicate destructiveHint=true, but the description clarifies when the destruction occurs. Slight gap: no mention of access loss on immediate cancel, but it's implied.

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: first clearly states purpose, second explains key behavioral nuance. No redundant information, front-loaded with critical details. Extremely concise 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 simple two-parameter tool, the description covers essential aspects: purpose, default vs immediate behavior, and the fairness rationale. It lacks explicit output description, but given no output schema and simple return likely, completeness is adequate.

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 input schema already has 100% coverage with descriptions for both parameters. The description enhances understanding by explaining the default behavior of the `immediate` parameter and implying the `id` parameter's role. This adds context beyond the schema, earning above baseline.

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's purpose as 'Cancel a subscription.' It specifies the verb (cancel) and resource (subscription), and distinguishes from sibling tools like query_subscription and refund_payment by focusing on cancellation behavior.

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 provides explicit guidance on default behavior versus immediate cancellation, telling the agent when to use `immediate=true`. However, it does not explicitly state when not to use this tool or compare with alternatives like refund_payment, which would strengthen use guidance.

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?

The description fully discloses behavior: returns a hosted checkout URL, payment completes automatically with no confirm step, explains money flow (buyer→Stripe→merchant, service never touches funds), and mentions authentication via HTTP header. Annotations (readOnlyHint=false) align with the write operation described, and no contradictions exist.

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 well-structured and front-loaded with the core purpose, then details optional features. At 7 sentences, it is concise but could be slightly tighter; however, every sentence adds value without redundancy.

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 6 parameters and no output schema, the description provides complete context: return value (hosted URL), behavior (automatic completion, no confirm), money flow, and optional behaviors. It adequately covers all necessary information for an agent to invoke the tool 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?

All 6 parameters are documented in the schema (100% coverage), and the description adds meaningful context: e.g., issue_invoice creates a VAT-ready invoice, collect_tax_id collects business tax IDs, and amount_eur has a concrete example. This enhances understanding beyond the schema alone.

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 it creates a payment link in EUR for Lithuania via Stripe Checkout Sessions, explicitly distinguishing it from sibling tools like create_subscription_link (subscriptions) and refund_payment (refunds). The verb 'create' and resource 'payment link' are specific and unambiguous.

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 use for one-time payments and provides guidance on optional features (invoice, tax ID) for specific scenarios, but does not explicitly state when not to use it or compare directly with siblings. However, the sibling tools have different purposes, so the risk of confusion is low.

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 indicate readOnlyHint=false and destructiveHint=false. The description adds that the amount is checked before creation and describes the buyer experience (URL, card entry, auto-charges). No contradictions.

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 sentences front-loaded with purpose. Some detail on buyer flow could be condensed, but no extraneous 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 tool with 5 parameters and no output schema, the description covers purpose, buyer experience, and guardrails. Missing error conditions or idempotency (not required), but sufficient for typical 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% with good descriptions. The description adds clarifications like 'per billing period in local currency major unit' for amount_eur and default interval month, but these are minor relative to 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 'create', the resource 'subscription checkout link', and specifies billing intervals. It distinguishes from sibling 'create_payment_link' which is for one-time payments.

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 explains the buyer flow and recurring nature, and hints at owner policy guardrails. It doesn't explicitly exclude alternatives but context from siblings (e.g., create_payment_link for one-time) provides implicit guidance.

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?

The description discloses that it queries Stripe directly, is pull-based, and explains the output behavior (paid=true when status PAID, and conditional invoice details). This adds value beyond the annotations (readOnlyHint, openWorldHint), and there is no contradiction.

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 three sentences, each earning its place. The first sentence states the core purpose, the second adds the mode of operation, and the third details the key output scenarios. No extraneous 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 tool with a single parameter and no output schema, the description fully covers the essential context: what it checks, how it works, and what the results look like, including edge cases like invoice URLs. No gaps.

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 documentation for session_id is sufficient and covers 100% of parameters. The description reinforces that session_id comes from create_payment_link, which is already in the schema description, so it adds no new semantic meaning.

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 'Check whether a Lithuania payment (created by create_payment_link) has been paid.' It uses a specific verb ('check'), identifies the resource ('payment status'), and includes context that distinguishes it from sibling tools focused on subscriptions and refunds.

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 explains when to use the tool (for payments created by create_payment_link) and its mode of operation ('pull-based, no webhook needed'). It does not explicitly list alternatives or say when not to use, but the sibling context and clear purpose make the usage context clear.

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 and openWorldHint=true. The description adds value by explaining the subscription status values and the condition for active=true, which is beyond annotation scoping.

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 sentences, each serving a clear role: purpose, accepted inputs, and status meanings. No wasted words, information is front-loaded.

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 query tool with one parameter and no output schema, the description effectively covers input format, return semantics, and edge cases like incomplete checkout. No obvious gaps.

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 the description reiterates the ID types. It adds the specific prefixes (cs_..., sub_...), which provides more precise formatting guidance than the schema alone.

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 checks a subscription created by create_subscription_link, specifies accepted ID formats (session_id cs_... or subscription_id sub_...), and explains the meaning of active=true and NOT_SUBSCRIBED_YET.

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 ties usage to subscriptions created by create_subscription_link and specifies required ID types, but does not explicitly state when not to use it or mention alternatives like query_payment_status.

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 details beyond annotations: full vs partial refund, policy check on amount before gateway. Annotations indicate destructiveness; description explains mechanism.

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 sentences, no redundancy. Action and default behavior in first sentence, parameter clarification and policy in following sentences.

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 all necessary info: input parameters, default/partial behavior, policy interaction. No output schema needed; description is 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 covers both params (100%), but description adds nuance: optional amount for partial refund, session_id ties to query_payment_status.

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?

Explicitly states 'Refund a paid payment' with specific resource and action. Distinguishes from sibling tools like cancel_subscription or create_payment_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?

Clearly implies when to use (refunding payments) and mentions policy guardrails. Does not explicitly list alternatives or when-not-to-use, but context is sufficient.

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