check_http3

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable behavioral context beyond annotations: no auth required, ~2-5s expected latency due to UDP handshake timeout, and the live QUIC probe to UDP/443. No contradiction with annotations.

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 sentences, front-loaded with the core purpose, and every sentence adds value: what it checks, how it checks it, what it returns, when to use it, and operational characteristics. No filler or redundancy.

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 single-parameter read-only check with no output schema, the description is complete: it explains the input, the three signals checked, the aggregate boolean return, use cases, exclusions, auth requirements, and expected latency. Nothing important is missing for an agent to select and invoke this tool correctly.

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 coverage is 100% for the single required parameter 'domain', and the schema already explains that it must be a domain name only with no URL, path, or port. The description does not add further parameter-level detail, but the schema fully carries that burden, so 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 and resource: 'Read-only HTTP/3 + QUIC support check for a domain.' It clearly enumerates the three combined signals and the aggregate result, making it distinct from all sibling tools.

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?

Explicit when-to-use guidance is provided: 'Use when validating CDN/Cloudflare HTTP/3 rollouts or auditing modern transport posture.' It also gives a when-not case: 'not relevant for mail-only domains.' However, it does not name a specific alternative sibling tool.

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