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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description adds genuinely new behavioral context: a per-call price of $0.002 USDC via x402, the accepted payment networks, and the fact that failed calls are free. That is exactly the kind of operational detail annotations cannot carry, though return/pagination behavior is left to the output schema.

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?

Two sentences: the first front-loads what the tool returns and how to filter it, the second front-loads cost and payment mechanics. No filler or restated title.

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 field listing is sufficient and the pricing/payment disclosure covers the main non-obvious risk of calling it. It could still say more about result limits or pagination behavior on large result sets, but nothing essential for a correct call is missing.

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 defaults and ranges are already documented per parameter. The description only echoes the filter names (keywords, location, distance, minimum salary) without adding syntax, formatting, or edge-case semantics beyond the schema, so the baseline of 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 the specific source (Reed Jobs API), the geographic scope (UK), and the returned fields, so an agent can tell it apart from the many other job-board siblings. It stops short of an explicit comparison with those siblings, but the source and region are unambiguous.

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: the UK scope and named filter dimensions suggest when the tool fits, but there is no explicit 'use this when' guidance, no mention of alternatives among the numerous other job boards, and no exclusions (e.g. non-UK postings).

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