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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description only needs to add context, and it does: it discloses that records are 'sourced' (provenance is returned) and that shared tags are part of the result. It stops short of explaining failure behavior for invalid or duplicate slugs.

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 no filler; the cardinality bound and key are stated before the returned content. Nothing is wasted.

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 no output schema, the description must carry return-value information, and it does so at a high level (side-by-side sourced records plus shared tags). For a one-parameter, closed-world tool this is nearly sufficient; only ordering and invalid-slug behavior are unmentioned.

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 single parameter already carries min/max/uniqueItems plus an example. The description's '2 to 4 Chelsea places by slug' merely restates those constraints and adds no new syntax or format guidance, 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 (Chelsea places identified by slug) and a specific operation shape (side-by-side comparison of 2-4 items). It implicitly distinguishes itself from the single-item get_place sibling and the search/list siblings by describing a multi-record comparison output. It loses a point only because the action verb is nominalized ('Side-by-side sourced records...') rather than stated directly.

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 2-to-4 bound implies the comparison scenario, but the description never says when to choose this over get_place or search_places, nor what to do if a slug is unknown. Usage is inferable from the name and the cardinality constraint but not explicitly guided.

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