recurly

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

The description adds context beyond the destructiveHint annotation by explaining the default term_end behavior and the effect on billing state, though it could mention irreversibility.

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 concise sentences with front-loaded purpose, no filler, and efficient explanation of optional behavior.

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?

Lacks information about return values or prerequisites like requiring an active subscription, and does not specify success/failure behavior, though it provides the API endpoint for reference.

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?

With 100% schema coverage, the description reinforces parameter meaning and adds value by clarifying default behavior for timeframe and specifying format for subscription_id.

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 'cancel' and resource 'subscription', and distinguishes the tool from siblings like pause by specifying it changes billing state and offering timeframe options.

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 (to cancel a subscription) and contrasts with pause by mentioning billing state change, but does not explicitly name alternatives or provide when-not-to-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 aligns with the readOnlyHint annotation by stating it fetches an account. No contradictions. It adds the specific ID format and API endpoint, which is sufficient behavioral context for a read-only 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, each serving a distinct purpose: the first explains what it does and how to identify the account, the second gives the API endpoint. No wasted words.

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 tool with one parameter, no output schema, and annotations covering safety, the description is complete. It includes all necessary details to use 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?

The schema description already covers the parameter format, and the tool description reinforces it with examples. This adds clarity but the schema already does the bulk of the work.

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 fetches one account by its ID or by a code prefix. It distinguishes from sibling tools like recurly_get_subscription or recurly_list_accounts by focusing on a single account retrieval.

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 how to format the account_id parameter (with or without 'code-' prefix), providing clear usage guidance. However, it does not mention when not to use this tool or compare directly to 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?

Annotations already declare readOnlyHint=true. Description adds the specific Recurly API endpoint (GET /subscriptions/{subscription_id}), providing useful context beyond annotations.

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, front-loaded with the main purpose, no unnecessary words.

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?

Simple tool with one parameter and no output schema; description sufficiently covers identification method. Could mention return format but acceptable given simplicity.

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 describes parameter subscription_id with details about format (no prefix or uuid-). Description does not add new meaning; baseline 3 due to 100% schema coverage.

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 'fetch one subscription' by id or uuid-prefixed string. Clear verb and resource, distinguished from sibling tools like list, cancel, pause.

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?

Implies usage when you have a specific subscription identifier, but no explicit when-to-use or when-not-to-use compared to listing or other operations.

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 provide readOnlyHint=true, so the description's 'List' is consistent. It adds pagination and filtering context but does not disclose behavior like rate limits, response structure, or cursor usage beyond the schema. Acceptable given annotations cover read-only safety.

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 a single sentence with no wasted words, front-loading the core action. It includes essential notes on pagination, filtering, and the API endpoint. Highly concise and well-structured.

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 list tool with 8 parameters and no output schema, the description is minimal. It does not explain how pagination works (e.g., cursor behavior), what the response format is, or filter combination rules. Could be more complete but satisfies basic needs given sibling distinctness.

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 does not add additional parameter meaning beyond the schema. Baseline 3 is appropriate since the schema already documents all parameters with descriptions and defaults.

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 the tool lists customer accounts, mentions pagination and filtering, and distinguishes from siblings which are about subscriptions, invoices, etc. The verb 'list' and resource 'customer accounts' 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 does not explicitly state when to use this tool versus alternatives like recurly_get_account. However, the context signals and sibling tool names imply this is for listing, not single retrieval. Lacks explicit when-not-to-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?

Annotations already indicate readOnlyHint=true, so the read-only nature is known. The description adds value by revealing the HTTP method (GET) and the two endpoint patterns ('/invoices' vs '/accounts/{account_id}/invoices'). This discloses behavioral variation beyond annotations, though it does not explain pagination or rate limits.

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 redundant words. The core purpose is stated first, followed by the optional scope. Every sentence provides unique value without elaboration.

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 listing tool with 8 optional parameters and no output schema, the description covers the two main modes and endpoints. It could mention that all parameters are optional and that pagination is handled via limit, but given the annotations and schema richness, it is largely 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 coverage is 100% with detailed parameter descriptions. The description adds minimal extra meaning beyond the schema—only clarifying that account_id can be an ID or code-prefixed, and that the list scope depends on its presence. Baseline 3 is appropriate since schema does the heavy lifting.

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 'List invoices across the site, or for one account when account_id is given'. It specifies the action (list), the resource (invoices), and the two modes (global or per-account). This distinguishes it from sibling tools that list other entities like accounts or subscriptions.

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 (to list invoices), but does not explicitly contrast with sibling tools or provide when-not-to-use guidance. It mentions the optional account_id for scoping, but no alternative strategies. Usage context is clear but not enriched with exclusions or comparisons.

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; the description adds that it is a GET request, which confirms safety. However, it does not disclose other behavioral aspects like pagination behavior or result limits beyond what schema provides.

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 brief, with one core sentence and an endpoint note. It is front-loaded and concise, though the endpoint detail might be considered extraneous for an AI agent.

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?

The description is minimal. With no output schema and a filtering list operation, more information about return shape or pagination behavior would be helpful for an agent to use 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?

Schema covers all 6 parameters (100% coverage). The description only references the state filter, adding no extra meaning beyond the schema's descriptions. Baseline of 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 it lists subscription plans, with optional state filtering. It distinguishes itself from sibling tools which operate on different resources (accounts, subscriptions, invoices).

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 listing plans but provides no explicit guidance on when to use this tool versus alternatives like list_subscriptions, nor any when-not-to-use conditions.

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, so the read-only nature is clear. The description adds the behavioral detail of endpoint routing based on account_id, which adds value beyond annotations. 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?

Two sentences, no wasted words. Purpose is front-loaded. Very 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?

Despite high parameter count and no output schema, the description covers core behavior and endpoint variation. Could mention pagination implicit from limit, but schema handles that. Minor gap, but overall 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 coverage is 100%, so baseline is 3. The description adds meaning to account_id by explaining the endpoint routing. Other parameters are well-documented in schema, so no further elaboration needed.

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 subscriptions, with optional scoping to an account or by state. It distinguishes from sibling tools like recurly_get_subscription (single) and mutation 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?

The description explains when to use account_id to switch endpoints, but doesn't explicitly state when not to use this tool (e.g., for single subscription use recurly_get_subscription). Good context but lacks explicit 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?

Annotations already mark the tool as destructive (write operation). The description adds that it 'changes billing state' and explains the resume/cancel behavior when `remaining_pause_cycles` is 0, providing useful behavioral context beyond the annotation.

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 sentences long, front-loads the core action, and includes essential details (resume behavior, billing impact, API endpoint). 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 the simplicity of the tool (2 parameters, no output schema) and the presence of annotations, the description covers the key aspects: what it does, how to use the resume feature, and that it modifies billing. It omits potential details like response format or permissions, but these are reasonable gaps for this level of complexity.

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 has 100% coverage with descriptions for both parameters. The description restates the resume/cancel behavior of `remaining_pause_cycles`, which is already in the schema, adding no new semantic meaning beyond reinforcing the usage.

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 specifies the action ('Pause a subscription'), the resource (subscription), and the scope (number of billing cycles). It includes a special case for resuming/canceling pauses, which distinguishes it from permanent cancellation. The title and API endpoint further reinforce clarity.

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 states when to use the tool (to pause for upcoming cycles or resume/cancel by setting cycles to 0). It does not explicitly contrast with the sibling `recurly_cancel_subscription`, but the context of pausing vs. canceling is implicitly clear.

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