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 a modest behavioral hint that results carry identifiers used for item lookup and search, but gives no detail on coverage, pagination, or storefront 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?

A single well-formed sentence that front-loads the core action and scope with no redundant or filler clauses. Every element earns its place.

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 one-parameter read tool with full schema coverage, an output schema, and annotations, the description covers purpose and the downstream use of the returned identifiers. Only the explicit relationship to sibling item/search tools is left unstated.

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% for the single parameter, and the description's 'US postal code' merely restates the schema's own 'US postal/ZIP code to search near.' Baseline 3 applies since the schema already carries the semantics.

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 (Find) plus resource (Instacart retailer storefronts) and constraint (serving a US postal code), and hints that the result feeds item lookup/search, which separates it from instacart_search/instacart_item. It does not name a specific sibling to avoid, so it falls just short of maximal 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?

Usage is only implied: the mention of 'identifiers needed for item lookup and search' suggests this is a prerequisite call for instacart_search or instacart_item, but the description never explicitly states when to use this versus those tools or any prerequisite/ordering.

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