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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so safety is covered. The description adds genuinely useful context beyond them: the auth requirement for search volume and the free tier without it, plus the concrete external systems queried (GitHub, npm, domains). Missing cost/quota detail keeps it short of a 5.

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 short sentences, zero filler, and the core action is front-loaded before the conditional pricing/auth caveat. Every clause carries information the agent cannot get from the name or title alone.

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 availability check with no output schema, enumerating the four things that get checked effectively previews the return content and is sufficient to call the tool correctly. Details like per-check result shape or partial-failure behavior are absent, but not critical here.

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%: the name constraints, the tlds default list, and the country default are all documented inline. The description hints at the TLD and volume dimensions but adds no syntax, limits (maxItems 10), or default behavior beyond what the schema already states, 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?

The description uses a specific verb ('One check') on a concrete resource (a product or brand name) and enumerates exactly what gets checked: domains per TLD, the GitHub account, the npm package, and search volume. That is far more informative than the title alone. It does not, however, distinguish itself from the sibling check_domains, which appears to overlap on the domain-per-TLD check.

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?

Usage is only implied: the reader infers this is an availability-check tool. It does add a conditional gating hint ('with a key the name's search volume. Free without the volume.'), which tells the agent volume data requires auth, but there is no explicit when-to-use/when-not or routing against the sibling check_domains.

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