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

Beyond the readOnly/idempotent annotations it discloses provenance semantics (crowd observations vs. owner_declared manifest, "never a verified fact"), how the strategy basis is derived (three independent agents vs. registry plain HTTP check with checked_at), the cost model (free daily allowance then 5 credits), and the asynchronous pending state with retry timing. These are exactly the traits annotations cannot express.

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 purpose is front-loaded in the first sentence and every later sentence carries operational content (provenance, basis, pricing, retry). It is somewhat dense with internal vocabulary (manifest_provenance, crowd_verified, registry_check) that could be structured as a short list rather than prose.

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 still explains what comes back (posture fields, strategy, optional manifest with provenance, basis with checked_at) and covers cost and retry behavior. An agent has enough to call it and interpret the result without further documentation.

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 description coverage is 100%, so host, agent_token and client_class are already well documented, including the enum values. The description adds only marginal cross-cutting context — that a registered key triggers an on-the-spot check and that agent_token ties the lookup to a quota — so baseline 3 applies.

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?

The first sentence gives a specific verb and resource — get a site's access posture, bot challenge, JS requirement, rate limit, machine interface, plus a derived fetch strategy — which is far more concrete than the title alone. It does not explicitly name or contrast with the sibling report_observation, so sibling differentiation is left implicit.

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?

The timing is stated precisely: "Before fetching a website." It also tells the agent what to do in the pending case (ask again in 15 seconds). There is no explicit when-not guidance or routing to report_observation, so it stops short of full alternative coverage.

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