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

Annotations already declare readOnly/openWorld/destructive=false, so the safety profile is covered. The description adds real context: the 14-day default lookahead, the soonest-first ordering, and the required Cotlet API key with app access. It does not describe pagination or result caps, so not a 5.

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 first two sentences are near-identical repetitions ('Viewing times of your saved homes, soonest first, with address and broker' / 'Returns the viewings of your saved homes... soonest first, with address and broker'), wasting the most prominent position. The prerequisite sentence earns its place, but the redundancy costs it.

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 no-output-schema read tool, the description usefully covers return contents (address, broker), ordering, default time window, and auth requirement. Enough for an agent to call it correctly; only missing caveats like result limits or empty-result behavior keep it from a 5.

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% and the single parameter already documents its default ('14 days ahead'), so the description's restatement of the same behavior adds little. Baseline 3 is appropriate when the schema does the documentation work.

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 (upcoming viewings of saved homes), plus return fields and ordering, so an agent knows exactly what it gets. It does not, however, name or contrast with the nearest sibling (hemnet_list_saved_homes), so it stops short of full sibling differentiation.

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 by the 'saved homes that have not happened yet' framing, and the API-key prerequisite is a useful gating note. But there is no explicit when-to-use vs. when-not, and no pointer to a sibling for a different scope (e.g., saved homes without viewings).

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