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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is known. The description adds genuinely useful context beyond them: no account or prop_id is required (auth-free), and it discloses the semantic of the response field ('is_active: true means covered'). It stops short of noting latency/caching or what a false/error response looks like.

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?

Roughly three short sentences, front-loaded with the discovery-stage framing and endpoint, with zero filler. Every sentence (identity, prerequisites, usage gate) earns its place.

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 one-parameter, read-only coverage check with an output schema present, the description supplies everything the agent needs: purpose, prerequisites, usage gate, and the interpretation of the key response field. Nothing material 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 description coverage is 100% and the single 'state' parameter is fully documented (short code or full name) in the schema. The description only reinforces that no account or prop_id is needed rather than adding new parameter semantics, so the baseline applies.

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+resource ('is this state served by beycome MLS?') and even names the underlying endpoint (GET /mls/is-covered). It is clearly distinct from the sibling tools (comps, estimate, listings, messages), so an agent can route without opening the 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?

Explicitly prescribes the workflow position ('Use before listing to confirm beycome operates in the property's state') and states the negative case ('If not covered, the listing flow does not apply'). Both when-to-use and when-not-to-use are covered.

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