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

readOnlyHint=true already tells the agent this is a safe read, so the description only needs to add context. It adds a little: 'full details' distinguishes a complete record from the summary shape other listing endpoints likely return, but it says nothing about permissions, error behavior for unknown ids, or representations.

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 nine-word sentence with the identifying qualifier ('by id') front-loaded and no filler. It is efficient, though its brevity borders on under-specification rather than pure conciseness.

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 one-parameter read-only getter with full schema coverage and no output schema, the description is just about sufficient to call the tool correctly. It still leaves open what 'full details' includes and how missing ids are reported.

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?

Only one parameter exists and schema description coverage is 100%, so the schema fully documents 'id' as the listing id. The description repeats the notion of lookup by id without adding format or validation detail, 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 combination: full details of one listing, keyed by id. That distinguishes it from list-oriented siblings such as search_listings and from mutation siblings like update_listing, though the description never names those alternatives 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?

'By id' implies the precondition that the caller already holds a listing id, which implicitly routes agents without an id toward search_listings. There is no explicit when-to-use/when-not statement or mention of prerequisites.

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