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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuine contextual behavior beyond that: the repost/staleness signal via latest_id and the concrete return payload (photos, dates), which an agent wouldn't infer from the annotations alone.

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, front-loaded with the core purpose and followed by an edge-case warning; no filler. Slightly compressed by the parenthetical examples, but every clause earns its place.

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 single-parameter read tool with an output schema, rich annotations, and a documented id format, the description covers purpose, return highlights, and the one real edge case (reposted/stale listings). Nothing needed to invoke it correctly is missing.

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 there is only one parameter whose format is already documented in the schema ('Listing id from search_listings, e.g. c-152'). The description's id examples are redundant with 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?

Specific verb+resource ('Full details of one listing by id') with concrete id examples and an enumeration of what's returned (description, photos, dates). An agent can distinguish this from search_listings and list_regions 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?

Gives a clear conditional: if latest_id is set, the record is a stale copy of a reposted listing and the newest should be used instead. It stops short of explicitly stating the retrieval workflow (e.g. 'get ids from search_listings first'), though the schema description on `id` carries that routing.

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