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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so safety is covered. The description adds genuine behavioral context beyond that: the returned value is Hemnet's estimate, homes need not be for sale, and it requires a Cotlet API key with access to this app.

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?

Front-loaded and readable, but the 'value Hemnet shows over time' idea is stated twice in near-identical wording, and the second sentence largely restates the first. Tightening would remove a redundant clause.

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 parameterless read tool with no output schema, the description supplies what an agent needs: the returned entities, the meaning of the value figure, the follow-scope caveat, and the API-key requirement. Only the sibling differentiation 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?

The tool takes zero parameters, which is the baseline-4 case. The description appropriately focuses on describing the return content rather than inventing parameter semantics.

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 (list) and resource (homes you follow), and clarifies scope as 'your own home and other homes you follow'. It is clear on its own, but never explicitly contrasts 'followed' homes with the sibling hemnet_list_saved_homes, so the distinction must be inferred.

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?

Provides no when-to-use, when-not, or alternative routing. The note that 'homes not for sale can be followed too' is contextual color, not usage guidance, and no sibling such as hemnet_list_saved_homes or hemnet_follow_home is referenced.

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