check_domain

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

Annotations already establish readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine non-obvious behavior: it performs a real DNS query that appears in the profile's log and analytics, takes a few seconds, and may lag recent changes. However, it does not otherwise enrich the declaration, so this lands at solid-but-not-rich.

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 answer and the outcome taxonomy before the caveats, and every clause carries information. It is a dense wall of clauses in one long sentence, which costs a little readability but wastes nothing.

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?

Covers the return-state taxonomy, the side effect (visible DNS query in log/analytics), latency, and staleness, and an output schema already documents the response shape. An agent has everything needed to call it correctly and interpret the result.

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 both 'domain' (with link-truncation behavior) and 'profile' (defaulting rules) are already fully documented in the schema. The description adds no syntax or format detail beyond that, so the 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?

States a specific verb+resource (check whether a domain is blocked by a profile) and enumerates the outcome space (BLOCKED with reason, ALLOWED with addresses, no such domain). That precise scope cleanly separates it from siblings like logs and watch_logs.

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 trigger ('when a site doesn't load or should be blocked') and names the alternative plus its selecting condition ('use logs or watch_logs for what devices really did'). The routing decision is fully determined by the text.

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