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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world). The description adds genuinely new behavioral context: the range comes from 'published industry tables and public quotes, not a bid from a mover', and distance is resolved from stored route data where possible. That tells the agent how much to trust the number and how the tool fills gaps, though it doesn't mention latency or failure modes.

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?

Three sentences, front-loaded with what is returned before the sourcing caveat and the when-to-use clause. Each sentence carries distinct information (output, trustworthiness/sourcing, invocation), with no filler.

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?

For a read-only estimator with no output schema, the description adequately covers the return shape (low and high with currency), the geographic scope, the sourcing, and the flexible distance inputs. Minor gaps remain around edge cases (e.g. unmatched origins or empty route data), but nothing essential to correct invocation 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 coverage is 100%, so the baseline is 3, but the description adds real meaning beyond the schema: it explains that the caller may pass a distance band, a mileage, or an origin/destination, and that the tool resolves distance from stored route data otherwise. This clarifies how the three distance-related parameters interact, which the schema alone does not.

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?

States a specific verb and resource – returns a planning cost range (low/high plus currency) for a household move – and scopes it to three countries. It also implicitly separates itself from request_moving_quotes by noting the figure is 'not a bid from a mover', so an agent can distinguish it from the sibling quote tool without opening a schema.

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 it when someone asks what a move might cost' gives a clear triggering context, and the 'not a bid from a mover' contrast steers agents away from treating it as a firm quote. It stops short of naming request_moving_quotes as the alternative for actual bids, so the routing is implied rather than explicit.

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