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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered elsewhere. The description adds no behavioral context beyond that - nothing about caching behavior (only the parameter schema mentions cache bypass), rate limits, or what happens when no SVCB record exists. With a rich annotation set the bar is lower, but this adds essentially nothing.

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?

Two compact sentences with the resource and standard front-loaded; nothing is padded. The second sentence is short but slightly ambiguous - it is unclear whether scan_domain invokes this tool or whether this is an alternative to it.

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?

An output schema exists and all parameters are documented in the schema, so return values and inputs need no further explanation. What remains missing is selection guidance in a crowded namespace of similar check_* tools, which is the one thing the description should have supplied.

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 all three parameters including the format enum and force_refresh cache semantics are already fully documented in the schema. The description contributes no additional parameter guidance, so the baseline of 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 ('Validate') and resource ('HTTPS/SVCB records'), plus the RFC 9460 standard and the capability being tested ('modern transport capability advertisement'). This is clear enough to act on, but it never distinguishes itself from near-siblings like check_dane_https or check_srv, which an agent could easily confuse it with.

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?

'Part of the scan_domain audit' gives a usage context, implying it is a component of a broader audit rather than a standalone entry point. However, there is no explicit when-to-use vs when-not, no mention of prerequisites (e.g., requires prior NS/DNSSEC checks), and no routing to or away from the overlapping DANE/SRV tools.

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