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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the set of fetched fields, but does not disclose auth needs, error behavior for an unknown ID, or any rate limits, so it adds only modest context beyond the structured fields.

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 tight sentences with the tool's scope and payload front-loaded, followed by the disambiguation clause. No filler.

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?

An output schema exists, so return values need not be explained, and the input is a single well-documented ID. For a simple read lookup, the description plus structured fields give the agent everything needed to call it 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 description coverage is 100%, so the schema already fully documents the single 'id' parameter, including that it is the numeric /stores/{id} path segment. The description's 'by numeric store ID' merely echoes this, adding no syntax or sourcing detail beyond the schema, so baseline 3 applies.

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 ('Fetch') and single resource ('one physical CarMax store'), enumerates the returned fields (name, address, contact details, opening hours, store-type flags), and names the siblings it is not ('carmax_stores to browse', 'carmax_search to find a store'). An agent can distinguish it from those siblings without opening any schema.

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: use this tool for a single store looked up by ID, and it names both alternatives with their purposes (browse vs. find). When and when-not is derivable directly from the text with nothing left to inference.

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