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

With annotations already covering read-only, idempotent, non-destructive and open-world behavior, the description still adds substantial context: default sort behavior, that price per acre is labeled listing vs estimate, per-row distance with near, group counts with groupBy, location page links, and that all data is Sepolia test data with no real-world effect. This is real value beyond the annotations.

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 sentence, with return behavior following. The sort/filter enumeration makes the paragraph dense, but nearly every clause carries information an agent needs.

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 an 18-parameter tool with no output schema and nested near object, the description covers filter dimensions, sorting, aggregation mode, row contents and the testnet caveat, which is close to complete. It stops short of clarifying how filters combine or how it relates to sibling tools, which keeps it off 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 description coverage is 100%, so the schema already documents all 18 parameters thoroughly, making baseline 3 appropriate. The description restates the filter and sort categories and adds labeling semantics for price per acre, but does not go far beyond what the schema already states.

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?

Names a specific verb and resource ('Search US land on Fabrica'), then immediately scopes it to 'land for sale and every other property on the network, mostly vacant lots and acreage', which is enough to tell it apart from siblings like list_land_for_sale, get_land_property and get_land_portfolio without opening a 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?

The description clearly frames this as a filtered multi-result search (and as an aggregate when groupBy is used), which implicitly tells the agent to prefer it over single-property or listing-only tools. It never explicitly names an alternative or an exclusion case, so it lands at clear-context rather than explicit when/when-not guidance.

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