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

Beyond readOnlyHint/idempotentHint/destructiveHint=false, it discloses distinctly behavioral facts: a just-in-time partial answer within ~2 seconds for never-measured domains, queuing for a full scan, 'nothing is guessed,' no overall score, and evidence tagged declared/observed/not_measured with timestamps. That is exactly the added context annotations cannot carry.

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 most important instruction (call before acting on a domain) is front-loaded, and every clause describes a distinct piece of the returned answer rather than padding. The second sentence is an unusually long run-on that strains readability, which holds it short of a 5.

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, so the description carries the full burden of describing the return, and it does so exhaustively — field categories, evidence provenance marking, and the degraded partial-answer path. Nothing needed to interpret or trust the result 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?

There is one required parameter with 100% schema description coverage ('Bare domain, e.g. example.com'), so the schema does the work. The description adds no syntax, normalization, or format detail beyond it, making the baseline 3 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?

The description states a specific verb (resolve) and resource (domain) and enumerates the payload of the answer: claims, observed serving per crawler identity, control, published-rule decisions, changes, and evidence. It never names a sibling tool (resolve_robots, scan_domain, preflight, best_source), so the agent must infer how this differs from those, which keeps it out of 5 territory.

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?

It gives an explicit trigger: 'Call before fetching from, citing, connecting to or transacting with a domain,' which is a clear when-to-use. It does not, however, state when NOT to use it or point to alternatives like scan_domain or resolve_robots, so the routing guidance is incomplete.

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