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 freshness context ('live', 'real time slots and timestamps') and distinguishes the ASAP option from scheduled days, but discloses nothing about rate limits, auth, or coverage limits. With annotations carrying the behavioral load, this is adequate but not rich.

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 sentence that is front-loaded with the resource and immediately scoped to a location and market. It is somewhat dense with a colon-clause listing returned content, but every element earns its place with 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 the description need not explain the return structure, and annotations cover the read-only/open-world profile. Between the complete schema and the stated purpose, an agent has enough to call this correctly; the only gap is the absence of any usage routing relative to Deliveroo's 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 description coverage is 100%, so the enum-like market values (uk, ie, fr, it, be, ae, kw) and the required latitude/longitude are fully documented in the schema. The description only echoes the 'supported national market' concept and 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?

The description names a specific resource (Deliveroo live delivery and pickup scheduling windows) and scope (for a location in a supported national market), so an agent can distinguish it from sibling tools like deliveroo_search or deliveroo_restaurant_menu. It does not explicitly name or differentiate against those siblings, keeping it at 4 rather than 5.

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: it states the tool works 'for a location in a supported national market,' which hints that latitude/longitude and market are needed. There is no explicit when-to-use, no when-not-to-use, and no mention of alternative tools for related queries (menus, availability).

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