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

Annotations already declare readOnlyHint=false, idempotentHint=true, openWorldHint=true, destructiveHint=false. The description goes further: it discloses the full-overwrite nature, that the call is FREE (no credits), that it writes to the operator's live Bing Webmaster account, and gives concrete error contract ({ ok:false, reason:'not_configured' | 'no_matching_site' }). This is substantial added 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?

Front-loaded with the operation and scope, followed by the mutation/free/key caveats, then the error contract. Dense but every sentence carries information; slightly long but nothing is wasted.

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?

No output schema exists, and the description compensates by specifying the error response shape and the credential/site-match preconditions. An agent has everything needed to invoke it correctly and interpret failure.

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 parameters are already well documented (crawlRate min/max 24 with its own description, projectId, ajaxEnabled). The description reinforces the 24-hourly-values rule and cites Bing's CrawlSettings JSON sample, which adds framing but no syntax the schema lacks. 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 (overwrites/saves) and resource (the project's matched Bing site's crawl-rate/AJAX-crawling config), and explicitly names the read counterpart get_bing_site_overview's GetCrawlSettings. An agent can distinguish it from the read sibling 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?

Clearly frames the tool as a mutation vs. the read alternative, and states preconditions (BYO BING_WEBMASTER_API_KEY, requires a verified site match). It stops short of explicit when-to-use/when-not phrasing, but the context for selecting it is clear.

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