Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and open-world nature are covered. The description adds that results come from an external autocomplete API and that limit is clamped to 20, which is modest extra context. No mention of result ordering, latency, or empty-result behavior.

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?

Front-loaded with the core purpose, then limit, then the routing hint. It is appropriately short, though the limit sentence duplicates the schema description almost word-for-word, which is wasted text.

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 present the return values need not be described, and annotations cover safety. The definition is largely complete for a simple two-parameter lookup, needing only a bit more on when to prefer it over rightmove_search.

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 description largely restates the schema's limit wording verbatim without adding format, syntax, or matching-behavior detail. Baseline 3 is appropriate when the schema carries the parameter burden.

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 states a specific verb and resource: 'Returns location suggestions from Rightmove's autocomplete API for a given query.' An agent can tell what it produces. Sibling differentiation is only partial – it names rightmove_search but not the relationship to it.

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?

'Use rightmove_search to search Rightmove properties' points the agent to the alternative tool, implying this one is for resolving locations rather than finding properties. It gives context but not an explicit when-to-use rule (e.g., 'call this first to resolve a location string').

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