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

The annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds that annual and monthly council tax are returned, but it does not explain rate assumptions or regional handling beyond naming a local authority rate.

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?

The description is short and front-loads the core purpose, then adds usage, inputs, returns, and a pointer to list_bundles. The input summary is somewhat redundant and contains the local-authority mismatch, but there is little waste.

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?

The schema and output schema are rich, and annotations cover safety, so most structured context is present. The description is broadly complete, but the 'local authority' versus 'region' inconsistency leaves a gap that should have been clarified.

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 100%, so the schema already documents band and region. However, the description says the inputs are band and 'local authority', while the schema actually exposes 'region'; this misnames a parameter and could mislead an agent.

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 gives a specific verb and resource: compute UK Council Tax by property band and rate. It clearly distinguishes this from the many other calculators by naming the tax and UK scope.

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?

It states a clear usage context: UK residents and home buyers, and points to list_bundles for related finance-UK calculators. It does not give explicit exclusions or name a sibling alternative, so it falls short of a 5.

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