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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the description doesn't need to. It does add real context by disclosing what comes back (full description, price, condition, approximate area, photos, seller), which matters because there is no output schema.

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?

A single front-loaded sentence with no filler; the field list carries useful information rather than redundancy. The fragmentary style is acceptable but slightly terse compared with full-sentence guidance.

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 single-parameter read tool with annotations covering safety and with the description enumerating return fields, an agent has nearly everything needed to call it correctly. Only edge behavior (invalid or missing id) is unaddressed.

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?

With one parameter at 100% schema coverage, the schema already explains listingId as coming from search results. The description adds no additional parameter meaning such as id format or behavior on an unknown id, so baseline 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?

"Read one listing" gives a specific verb plus resource, and the enumeration of returned fields (description, price, condition, area, photos, seller) makes scope concrete. The singular "one listing" implicitly sets it apart from the search sibling, but no sibling is named explicitly.

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?

Usage is only implied: fetching a single listing's detail. There is no explicit statement of when to prefer this over search_listings (e.g., after obtaining an id), and no exclusions or prerequisites are stated beyond what the schema hints.

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