bing_sites_list

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

Annotations already declare readOnly/idempotent/non-destructive, but the description goes well beyond them: it discloses that verification secrets (AuthenticationCode, DnsVerificationCode) are redacted and unreachable via any MCP tool, that an empty result carries an empty_response label meaning silence rather than a clean bill of health, and that certain fields are untrusted data. These are real behavioral constraints an agent could not infer from the schema or annotations.

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 correctly: purpose, then usage, then the sibling exclusion, then return shape, with the safety caveats after. It is longer than most definitions and the operator CLI/UI detail is slightly tangential, but nearly every sentence addresses a distinct decision the agent must make, so the length is mostly earned.

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?

With no output schema, the description carries the full burden and does so: it enumerates the returned fields, explains the redaction of sensitive fields, and defines the empty-response edge case so it cannot be misreported. Nothing an agent needs to call and interpret this tool correctly is missing.

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 tool takes zero parameters, so per the baseline this is a 4. The description does describe the shape of what comes back (one entry per site, Url and IsVerified), which is useful, but there are no parameter semantics to add beyond that.

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?

Opens with a specific verb and resource ('List every site on the Bing Webmaster account') and immediately adds scope detail ('with its URL and whether it is verified'). It explicitly names the sibling it must not be confused with (bing_site_roles), so an agent can distinguish it without opening another 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?

Gives an explicit when ('the user asks which sites this account owns or whether a property is verified') and an explicit when-not with the correct alternative ('Do not use this to see who can edit a site; call bing_site_roles'). Both the positive trigger and the exclusion route to a specific sibling.

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