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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description goes well beyond that: it discloses the derivation (OpenStreetMap, 300 m coastal band, ray-cast to the shore past buildings, woods, dunes and cliffs), states the accuracy model (ground-level estimate; floors, trees and relief unknown), and warns that absence is not proof of no view. This is exactly the behavioural context an agent needs to interpret results honestly.

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 content is dense and mostly earns its place, but the structure is poor: the hardest, most convoluted sentence is first, and the reader must decode "around a place whose sun goes down (or comes up) into the sea, month by month" before reaching the clear material. The methodology clause is long and the stray "month by month" is dead weight.

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?

There is no output schema, so the description carries the return burden — and it partly does, mentioning distance to the shore and the latest sale, plus the caveat about false negatives and where the same field reappears. For a 7-parameter, read-only search tool this is largely complete, though the exact shape of a returned record (field names, ordering beyond "nearest first") is left vague.

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 the schema already carries all seven parameters and the 3 baseline applies. The description adds only marginal value — it explains the sun concept ("whose sun goes down (or comes up) into the sea") which maps to the sun enum, and mentions distance-to-shore output — while the phrase "month by month" introduces confusion since no month parameter exists.

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 tool returns sale addresses with a sea view, and the title plus the second sentence ("France's sale addresses within 300 m of the coast") make that discernible. But the opening sentence — "The sale addresses around a place whose sun goes down (or comes up) into the sea, month by month" — is garbled and forces the agent to reconstruct the purpose rather than read it. The sibling cross-reference at the end helps distinguish it, but the core statement is not front-loaded clearly.

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 implied rather than stated: it tells the agent the same view surfaces as sea_view on sales_at_address, recent_sales and appraise_listing, which signals overlap, but it never says when to prefer this tool over those siblings or when it is the wrong choice. The instruction to report a negative as "may still see the sea from upstairs" is useful interpretive guidance, but no explicit when/when-not/alternative routing is given.

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