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

Annotations only declare readOnlyHint and openWorldHint; the description adds materially more — the tool is currently paused and will answer SOURCE_UNAVAILABLE uncharged, results carry a mandatory attribution array and disclaimer that must be reproduced, and the data has an explicit freshness period. Those are operational facts the agent cannot infer from structured fields.

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 and metric list are front-loaded, and nearly every sentence carries distinct information (routing, exclusions, pause state, attribution duty). It is a long single block, though; the attribution and disclaimer clauses could be compressed without loss.

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, the description needn't explain return shape — yet it still flags the 'attributions' array and disclaimer as pass-through obligations, which is the one thing the schema can't enforce. The paused/SOURCE_UNAVAILABLE behavior covers the main failure mode an agent would otherwise mishandle.

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 both parameters are already documented, including the accepted area forms and the regionType hint. The description only adds a geographic boundary ('Western Washington focus'), which is a mild constraint but not format or validation detail beyond the schema. 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 resource (latest Redfin market snapshot) and enumerates the exact metrics returned (median sale price, YoY change, days on market, months of supply, percent above list), plus scope ('ZIP, neighborhood, city, or county'). It explicitly distinguishes itself from wa_comps and wa_market_trends, so an agent can pick 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?

Gives the triggering question pattern ('how is the market in X') and names two alternatives with the conditions that select them: wa_comps for recorded sale prices, wa_market_trends for price-index trends. It also states a hard exclusion ('aggregate statistics only — no individual listings, parcels, or people'), which is exactly the when-not guidance an agent needs.

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