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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description usefully adds what is returned (bidding state, price, bids, leader, auction status), but says nothing about pagination, result caps, or freshness/latency of the live state on a possibly large item list. With annotations doing the heavy lifting, this is an adequate but modest addition.

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?

Two sentences, zero filler. Purpose and return fields come first, and the sibling-routing sentence follows, so the most important selection information is front-loaded.

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 read tool with both annotations and an output schema, the description covers purpose, routing, and returned fields adequately. The only material gap is behavior for potentially large result sets (pagination/limits), which the output schema alone does not address.

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%, and the single required parameter is documented in the schema as the 'eBay Live stream/event id (required).' The description's `id` reference merely reinforces this rather than adding format, sourcing, or lookup guidance. Baseline 3 applies when the schema carries the semantics.

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 ('Fetch') plus the exact resource ('currently featured and auction item records for an eBay Live stream') and enumerates the fields returned (bidding state, price, bids, leader, auction status). It explicitly names the three siblings it is not (ebay_live_stream, ebay_live_streams, ebay_item), so an agent can distinguish it 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?

The description routes the agent by naming each alternative and the condition that selects it: ebay_live_stream for one stream's details, ebay_live_streams to discover streams, ebay_item for a product listing. This leaves little to inference about when this tool is the right choice.

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