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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds the shape of what is returned (field name, display name, property types) and the REST path, which is genuinely useful since there is no output schema, but it says nothing about filtering behavior or result size.

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?

Two compact sentences, front-loaded with the resource definition before the endpoint reference. Nothing is padded, though the trailing raw path is marginal value for an agent.

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 simple read-only list tool against a fully documented 4-param schema with annotations covering safety, the description plus structured fields are sufficient. The missing piece is sibling differentiation, but nothing required to invoke the tool correctly is absent.

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%, including the idx_id example, the fields wildcard behavior and the enum for filter_field. The description adds no parameter information beyond the schema, so 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 and resource: lists searchable MLS fields with field name, display name and property types. It's clear what the tool does, but it never distinguishes itself from close siblings like idx_list_mls_property_types or idx_list_mls_locations, which an agent could easily confuse it with.

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?

There is no when-to-use guidance at all: no statement about when this is needed versus idx_list_mls_property_types, and no mention that idx_id must first be obtained from idx_list_approved_mls (that hint lives only in the schema). The agent must infer usage entirely from the name.

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