b_set_apikey

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

Without annotations, the description takes on the burden. It discloses that validation occurs via GetUserSites before saving, which is a key behavioral trait. However, it lacks details on whether the tool overwrites existing keys, error handling, or authentication requirements beyond the key itself.

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 description is two sentences and gets straight to the point: what the tool does, validation behavior, and where to get the key. Every piece of information is necessary and 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?

Given the simplicity of the tool (single parameter, no output schema), the description is sufficiently complete. It covers purpose, parameter source, and validation. Could optionally mention idempotency or update behavior, but not essential.

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?

The schema covers the parameter fully (100% coverage) with a description. The tool description adds value by explaining where to get the API key, which is not in the schema. This extra context helps the agent understand how to obtain valid input.

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?

Clearly states the tool saves the Bing Webmaster Tools API key, with a specific verb ('Save') and resource ('API key'). Differentiates from sibling tools like bing_sites_get, bing_submit_url, etc., which deal with other aspects of Bing Webmaster Tools.

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?

Provides context on where to obtain the key ('Get it at Bing Webmaster Tools → Settings → API access → API Key') and mentions validation via GetUserSites. However, it does not explicitly state when to use this tool versus alternatives like b_auth_status, nor does it give conditions for when not to use it.

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