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

Annotations already communicate the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), so the description need not repeat those. It adds useful context about the return payload (full description and store prices) but does not disclose additional behavioral traits such as error handling, rate limits, or authentication requirements. This adds some value beyond annotations but not extensive behavioral detail.

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?

A single, front-loaded sentence states the action, the key prerequisite, and the return value without any filler or redundant information. Every clause earns its place, making it easy for an agent to parse quickly.

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 tool's simplicity (one required parameter, no nested objects), a valid output schema, and robust annotations, the description is complete. It tells the agent what input to provide, where to get it, and what the tool returns. No critical calling information is missing 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?

The input schema provides no description for the required 'id' parameter (schema coverage 0%), so the description carries the full burden. It explicitly explains that the id is the add-on slug returned from 'search', giving the agent the origin and format of the value. This fully compensates for the missing schema detail and leaves no ambiguity about the parameter's 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?

States a specific verb ('Retrieve'), a resource ('one add-on'), and the source of the identifier ('the id returned from search'). It also specifies the return content ('full description plus every current store price'). However, it does not explicitly distinguish itself from the sibling tool 'get_addon', which may perform a similar retrieval, so it falls short of full sibling differentiation.

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 clear contextual guidance by instructing that the id comes from the search tool, implying a search-then-fetch workflow. However, it does not mention when to use this tool instead of alternatives like get_addon or search_addons, nor does it state any exclusions. The guidance is implied rather than explicit.

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