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 only the scoping detail that branch_type distinguishes store type; it says nothing about auth, error behavior, or the freshness/completeness of the record, so it clears the lower bar but adds modest value.

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, front-loaded with what the tool returns and followed immediately by the routing guidance. Every clause 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 read-only detail fetch with a 100%-documented schema and an output schema, the description covers purpose and routing adequately. The only loose end is the unexplained branch_type reference, which the output schema presumably covers, so completeness is strong but not flawless.

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 documents uname and market fully, and the description adds no format or syntax detail beyond them. The mention of 'branch_type' is ambiguous since it is not an input parameter, which slightly muddies rather than clarifies semantics; 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 resource ('Deliveroo restaurant, grocery, or shop record') with the exact identifiers ('uname' and national market). It also distinguishes itself from siblings by naming deliveroo_search and deliveroo_restaurant_menu, so an agent can route without opening a 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 says to use deliveroo_search to find a branch and deliveroo_restaurant_menu for its products, establishing both the prerequisite step and the alternative for a different need. Nothing about when to pick this tool over the siblings is left to inference.

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