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

Annotations already cover read-only/idempotent/closed-world, and the description adds genuinely new behavioral context: the CAD data source, the fact that Texas does not disclose sale prices, and that no sale price, market value or offer price is returned. This prevents a major misread of the output; it stops short only of discussing staleness, coverage gaps, or failure modes for parcels outside the two counties.

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 scope are front-loaded in the first clause, and short declaratives ('CAD-based, not an appraisal', 'Counts as a property lookup. Read-only.') are efficient. The long internal enumeration of returned values is partly redundant with the existing output schema, costing a little tightness.

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 one well-documented parameter, an output schema, and rich annotations, the description supplies everything else an agent needs: county coverage, data provenance, the comparable-selection rule, and an explicit statement of what the tool does not provide. No material gap remains for correct invocation.

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 pattern already encodes the County:account form, so the baseline is 3. The description adds meaning by tying lead_id to the supported county set ('Any Dallas or Collin parcel by lead_id (County:account)'), clarifying the accepted input domain beyond the regex.

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?

The description opens with a specific verb and resource ('Estimate a land-value range for one Dallas County or Collin County, Texas parcel from appraisal-district (CAD) land values') and immediately enumerates the inputs used (CAD land/improvement/market values, comparable-parcel $/sqft quartiles). An agent can distinguish it from generic lookups like get_property or comps_for_address because it states the derived output and the county scope.

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?

It gives scope conditions ('Any Dallas or Collin parcel by lead_id') and a categorization hint ('Counts as a property lookup'), which implies when to reach for it. But it never names an alternative sibling (e.g. comps_for_address, get_property, analyze_deal) or states explicit when-not conditions, so routing is left partly to inference.

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