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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds real value beyond them: the data source (public Bing news HTML/async pages) and a concrete failure mode (503 on challenge page or unusable HTML), which the agent cannot get from structured fields.

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 and locale defaults are front-loaded, and the alternative is placed last. Some lines duplicate schema content (Query required, Count clamp), costing a little efficiency but not enough to hurt readability.

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 values needn't be explained, and annotations handle the safety profile. Between the source note, 503 failure mode, parameter defaults and sibling pointer, the description is nearly complete for a news search tool.

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 100% schema description coverage, the schema already documents all five params including defaults and the 1..50 clamp. The description largely restates Query and Count rather than adding format or syntax meaning, so the baseline 3 is appropriate.

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 ('Returns normalized Bing news search results'), plus scope ('for a query string'). It explicitly names the sibling bing_search as the web-results alternative, so an agent can tell the two apart without opening either 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?

Routes the agent to bing_search for Bing web results instead of news, giving a clear alternative. It lacks explicit when-not-to-use-this-itself criteria (e.g. no news index vs web index distinction beyond the sibling pointer), but the guidance is actionable.

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