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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so safety is covered. The description adds a genuinely useful behavioral constraint beyond that: hidden reserve and reserve-met status are never revealed before close, which prevents an agent from expecting or requesting that information. It does not cover error behavior for invalid auction_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?

The definition is short and front-loaded: purpose, then usage, then the caveat, then an example. The opening "Auction status." sentence duplicates the title and earns little, but everything after it is efficient and well-ordered.

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 single-parameter, idempotent read tool with full annotation coverage and no output schema, the description supplies what matters: the fields returned and the reserve-visibility caveat. Only the behavior on nonexistent or closed auctions is left unspecified, which is a minor gap.

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 description coverage is 100% for the single auction_id parameter, so the schema already carries the semantics. The inline example shows the call shape but adds no meaning about ID format or provenance beyond what the schema states, which is the baseline case for high-coverage schemas.

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?

"Auction status" alone restates the title, but the WHEN clause makes it concrete: it returns current high bid, start price, and ends_at. That tells an agent exactly what data this read tool yields. It does not explicitly distinguish itself from siblings like auction_bid or auction_close, so it stops short of a 5.

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 "WHEN: view auction status, current high bid, start price, and ends_at" clause gives clear selection context for reading auction state. However, no exclusions or alternatives are named (e.g., which sibling to use for bidding or closing), so the agent must infer that this is read-only viewing versus the mutating siblings.

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