check_srv

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the bar for additional disclosure is lower. The description still adds meaningful behavioral context: parallel probing of 19 prefixes, flagging insecure plaintext services, and the no-match caveat. This goes beyond what the annotations alone convey.

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 description is three dense sentences with no filler. The first front-loads the action and scope, the second explains outputs and flagging behavior, and the third provides an important caveat plus usage guidance. Every sentence earns its place.

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?

For a read-only, idempotent tool with full schema coverage and an output schema, the description is complete. It covers what is probed, what is returned, how to interpret negative results, and when to use the tool. Nothing needed to invoke it correctly 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?

Schema description coverage is 100% and each parameter (domain, format, force_refresh) is documented in the schema. The description does not add parameter-specific meaning, but it doesn't need to because the schema carries the load. Baseline 3 is 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 opens with a specific verb ('Map') and a precise resource ('a domain's DNS-visible service footprint'), then names the 19 SRV prefixes and what the tool returns. This differentiates it from siblings like check_svcb_https, which targets a different record type.

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 description explicitly states when to use it: 'Use when asked to map DNS-visible services or flag insecure service advertisements.' It also adds a valuable interpretation caveat about empty results not proving absence of services. It does not name sibling alternatives or explicit exclusions, so it falls just 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.