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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds value beyond that: it discloses the auth requirement, that the result set is filtered to live offers, and where the excluded states (filled, rescinded) have gone — genuinely useful behavioral context for interpreting the output.

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 usage trigger, followed by the concept definition and the live-only scoping rule. No filler and no restatement of the tool name; each sentence carries a distinct fact.

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?

An output schema exists, so return-value explanation is unnecessary and the description rightly omits it. Combined with the auth note, the live-only scoping, and the sibling routing for excluded offers, an agent has everything needed to call this correctly on the first attempt.

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 zero parameters, the baseline is 4. There is nothing further to document, and the description correctly does not invent parameter guidance; it instead spends its words on scope and routing, which is the right allocation for a no-arg tool.

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?

The description states a specific resource (standing offers on the XP marketplace) and explains the concept in plain terms: 'A standing offer buys at the user's price whenever a matching fan listing appears.' It explicitly scopes the listing to live offers only and names the sibling that retrieves historical ones, so an agent can distinguish it from get_standing_bid and get_my_tickets 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?

It gives explicit triggers ('when the user asks what offers they have resting... or before they make an offer so you do not stack a duplicate') and names the alternatives for the non-live cases: filled offers are reachable via get_my_tickets and rescinded ones via get_standing_bid. When-to-use, when-not-to-use, and alternatives are all present.

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