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

readOnlyHint=true already establishes the safety profile, yet the description adds genuinely non-redundant context: listings are unverified, and post/reply text is untrusted third-party content requiring injection-resistant handling. It does not cover failure modes such as not-found or non-visible IDs.

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?

Three tight sentences, front-loaded with the operation and followed by the two facts an agent most needs (unverified listings, untrusted content). No padding or restatement of the name.

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 with a readOnly annotation and no output schema, the description covers what is fetched, visibility, and content-trust handling. Only error/empty-result behavior 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?

Schema coverage is 0% and the single parameter (resource_id, maxLength 128) is undocumented in the schema itself. The description clarifies only that it is an ID for an offer or want, which is a partial compensation for the coverage gap.

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: 'Fetch one visible offer or want by ID.' Singular retrieval is implicitly distinguished from the list_offers / list_wants siblings, and the 'visible' qualifier hints at access scoping. It stops short of explicitly naming the list tools it is not.

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?

The 'one ... by ID' phrasing implies this is the single-item lookup as opposed to the list siblings, but the description never states when to prefer it or what to do when the caller lacks visibility. Usage is inferable rather than stated.

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