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

Annotations already cover the safety profile (readOnly, non-destructive, open world), and the description adds context beyond them: results are account-scoped ("approved for display on the account") and carry IDX ids and names. It stops short of describing result size, ordering, or any pagination/rate behavior.

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 sentences plus the endpoint: the return content is front-loaded, the downstream usage note follows, and the raw HTTP path is appended compactly. No sentence 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?

For a simple, parameter-light read with no output schema, the description supplies enough: what entities come back, what identifiers they carry, and how those identifiers are consumed elsewhere. Only the shape of the returned objects beyond id/name is left unspecified.

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?

The single optional `fields` parameter is fully documented in the schema (100% coverage, including the ["*"] wildcard and size-saving advice). The description adds nothing about it, so the baseline 3 applies since the schema carries the burden.

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 (list MLSs approved for display on the account) and names what is returned (IDX ids such as a001 and names), which an agent cannot infer from the name alone. It also positions itself relative to the other MLS tools, though it does not name a specific sibling it could be confused 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?

"Use the id in the other MLS tools" gives a clear downstream usage instruction that tells the agent this is a prerequisite/feeder call for the MLS-related siblings. There are no explicit exclusions or negative conditions, which keeps it below a 5.

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