ls_get_subscription_item

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and non-destructive. The description adds critical behavioral context beyond annotations: the price record's effective_unit_price is the actual charge per unit, whereas unit_price is vestigial or per-package depending on pricing model. This insight directly affects how the agent interprets data, adding value beyond the structured hints.

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 with the main purpose first and the include caveat second. Though the second sentence is dense, every clause serves a distinct purpose (what include=price returns, the field to read, why unit_price is unreliable). No fluff; it could be slightly more organized but remains 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 get-by-id tool with no output schema, the description is thorough: it tells the agent what to expect (quantity, pricing, subscription), how to retrieve the price record, and what to trust in the response. Given only two parameters and no complex nested structures, it covers all essential calling knowledge. Error scenarios are not described, but that is acceptable for a simple read operation.

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% for both parameters, but the description adds semantic depth: it explains the special include=price value and its effect on the response. The subscriptionItemId is straightforward, but the description's treatment of include goes beyond the generic schema description ('Comma-separated related resources') by identifying a specific useful inclusion and its output nuance.

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?

Clear verb 'Get' with specific resource 'subscription item' and explicit scope ('by ID'). Distinct from ls_list_subscription_items by the singular 'specific' phrasing. Also specifies what is included (quantity, pricing, associated subscription) and the price-record 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?

Provides concrete usage guidance for the include parameter ('pass include=price') and explains which field to read (effective_unit_price vs unit_price). While it doesn't explicitly say 'use this instead of ls_list_subscription_items', the 'specific... by ID' phrasing implies the singular use case. No exclusions are given, but the context is clear.

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