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

No annotations exist, so the description carries the full burden, yet it only discloses the 10-area cap. It is silent on the subscriber-token auth requirement (only visible in the schema), rate limits, error behavior, and what the comparison returns.

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 with the constraint and use cases front-loaded and no filler. The 'PRO' prefix is terse and slightly opaque but does signal tiering.

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 annotations and no output schema, the description should do more to explain the comparative return shape and the paid-tier auth requirement. It covers what the tool compares but leaves how it authenticates and what comes back to inference.

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 coverage is 75% and documents measure, pattern and access_token, so the description's main added value is the 'up to 10 postcodes' limit, which the schema does not state. It adds nothing about the measure/pattern semantics or default behavior beyond the schema.

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?

Names a specific verb (compare) and resource (median and percentile pay across postcodes), plus the cap of up to 10 areas. It does not explicitly name its siblings (area_salary, salary_percentiles) to steer selection, but the multi-area comparison scope implicitly distinguishes 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?

Gives use cases ('for relocation, hiring and pricing') which imply when to reach for it, but never states when to use area_salary or salary_percentiles instead, nor any prerequisites beyond the 'PRO' tag.

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