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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description only needs to add substance. It does, by defining what 'similar' means (rent, size, same area) and that results are live listings rather than historical. It omits ordering of results and that the result count is capped by the limit parameter.

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 short sentences, front-loaded with the purpose, then usage, then input format. No redundant or filler wording; every sentence carries information an agent needs.

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?

A simple two-parameter read tool with an output schema, so return values need no explanation. Purpose, trigger, and input format are all present; only the behavior of limit and result ordering are unaddressed.

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 50%: apartment is documented in the schema and the description restates the same accepted formats rather than adding new meaning, while limit has no description anywhere beyond its numeric bounds. Partial compensation for the gap, so a 3 is appropriate.

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 resource and scope: 'Live alternatives near an apartment: similar rent and size in the same area.' An agent can distinguish it from search_apartments because it is anchored to one apartment and constrained by similarity criteria, though no sibling is named explicitly.

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 concrete triggering conditions: 'when an apartment is rented or the renter wants more options.' Clear context for use, but it never states when to prefer search_apartments or building_report instead, so the routing choice is left partly implicit.

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