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

Annotations only declare readOnlyHint and openWorldHint. The description adds genuinely non-obvious behavior: the endpoint can take ~1 minute on a cold query, timeouts are safe to retry, no account or prop_id is required, and photo/listing-link fields are stripped to shrink the response. This is exactly the extra context annotations cannot carry.

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?

Purpose is front-loaded, followed by filters, usage routing, and behavioral caveats in short scannable lines. The retry advice is slightly conversational but each sentence conveys actionable information; nothing is redundant.

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?

With an output schema present, return shape needn't be explained, and the description still notes which fields are stripped. For a 13-param read-only discovery tool it covers purpose, routing, latency, and auth prerequisites without gaps.

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 all 13 parameters are already documented, including the property_type enum values. The description only summarizes filter categories (price/beds/baths/area/lot/type), which mirrors the schema rather than adding meaning. Baseline 3 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 — sold comparable listings near a location — and even names the underlying endpoint (GET /comps). It distinguishes itself from siblings by naming beycome_estimate as the companion tool, so an agent can place it 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?

"Use during discovery to support pricing alongside `beycome_estimate`" gives clear context and names a related tool. It does not state when to prefer one over the other (exclusions), so it stops short of a 5.

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