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

Goes well beyond the annotations (openWorldHint, idempotentHint, non-destructive) by disclosing that it performs an outbound HTTPS fetch, enumerating the 404/409/403 failure modes and their causes, and specifying the credential scope and workspace-claim prerequisite. This is exactly the preconditions-and-failure-modes context an agent needs before invoking.

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-loads the core action and the comparison mechanism before layering on error codes and prerequisites, and every sentence carries operational information. It is dense and somewhat run-on (several sentences packed with status codes), but no content 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?

With no output schema, the description does cover returns at a high level — success verifies the domain, failure returns reason and message, and 409/404/403 cases are named. A short note on what a successful verification changes for the workspace would close the last gap.

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 the baseline is 4. The description still implies the subject domain comes from the workspace's published protocol rather than an argument, which is useful framing, but there is nothing further to document.

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 ('Check the Personal Agent Protocol file you published') and immediately explains the mechanism: fetching https://<domain>/.well-known/poppy.json and comparing it against what get_agent_protocol returns. This clearly distinguishes it from sibling verifiers like verify_storefront_domain or verify_webhook_signature.

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 rich operational context: it only applies when agent protocol files are enabled (404 otherwise), requires a routing-write credential, and refuses sandbox keys from self-registration with a 403 until a human claims the workspace. It references get_agent_protocol as the comparison source but doesn't explicitly route the agent away from similarly-purposed siblings, keeping it short of a 5.

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