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 one useful behavioral nuance — 'whether it currently accepts orders' signals a live, time-sensitive field — but says nothing about auth, rate limits, or data freshness beyond that.

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 front-loaded sentence with zero filler; the key ('by unique_name') and the returned fields are stated immediately, and nothing is redundant.

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 structure need not be explained, and the description still previews the fields. For a single-parameter read tool this is essentially complete, with only explicit usage routing to siblings left out.

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% and the schema already explains unique_name as a slug from a search response. The description merely restates the key name, adding no format, casing, or sourcing detail beyond what the schema provides. Baseline 3 is appropriate.

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+resource ('restaurant detail by unique_name') and enumerates the payload (address, primary cuisine, rating, order acceptance). This cleanly distinguishes it from sibling justeat_search (discovery) and justeat_restaurant_menu (menu contents).

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?

The phrase 'by unique_name' implies this is a follow-up call after a search, but the description never states when to prefer this over justeat_search or justeat_search_filters, nor any preconditions. Usage is inferable rather than explicit.

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