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 useful context that branch_type disambiguates restaurant/grocery/shopping stores, but says nothing about auth, rate limits, or market-scoping behavior beyond the schema.

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 dense sentence, front-loaded with the resource and keys, followed by the returned fields. Nothing is padded, though the parenthetical about branch_type is slightly cluttered.

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?

With an output schema covering return values and annotations covering the safety profile, the description only needs to establish identity and inputs, which it does. The main missing piece is explicit routing from search/menu siblings.

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 uname and market are already fully documented, including the market enum values. The description restates the two inputs but adds no syntax or format detail beyond the schema, so the 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 resource and lookup key: 'restaurant, grocery, or shopping-store detail by uname and national market', and clarifies the branch_type distinction. It is clearly a detail-fetch tool rather than a search or menu tool, though it never names its siblings (deliveroo_search, deliveroo_restaurant_menu) to sharpen the contrast.

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: 'by uname and national market' hints the caller must already hold a uname, but there is no explicit when-to-use, when-not, or pointer to deliveroo_search as the source of the uname or deliveroo_restaurant_menu for menus. The routing logic is left for the agent to infer.

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