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

Goes well beyond the annotations: discloses the preview-then-confirm two-phase flow, that only confirm=True returns success=true, the required auth and write:bids scope, and that real money is at risk. The destructiveHint=true annotation is reinforced rather than merely repeated, giving the agent genuinely new behavioral context.

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?

Purpose is front-loaded, followed by sequencing, constraints, and alternatives in a tight logical order. Despite its length, every sentence carries operational weight (preview contract, auth scope, sibling routing).

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?

With an output schema, full schema descriptions, and annotations all present, the description still adds the safety-critical pieces an agent needs: the mandatory preview step, scope requirements, and the money-at-risk warning. Nothing material 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%, so the baseline is 3, and the schema already documents each parameter thoroughly. The description adds cross-parameter semantics not in the schema: confirm=False previews a fee-inclusive total with no bid placed, and only confirm=True yields a successful submission.

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 ('make an offer on an open XP listing') and immediately distinguishes itself from buy-now and browse tooling. An agent can tell it apart from siblings like buy_listing_now, accept_offer, and create_standing_bid 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?

Explicit when-to-use ('when the user wants to make an offer on an open XP listing'), explicit when-not ('Do not use for browse / discovery'), and names concrete alternatives ('use search_events and get_ticket_listings' for buy-now). It also prescribes the required two-phase sequencing, leaving nothing to inference.

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