Internet connectivity

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

Annotations declare readOnlyHint=true and openWorldHint=false. The description adds the diagnostic breakdown (which check failed) and clarifies it's a status read, not a configuration change. It doesn't describe return format or error handling, but for a read-only status tool the provided context is adequate.

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 sentences, zero wasted words. The primary purpose and usage guidance are front-loaded, and the diagnostic detail is concise. Perfectly sized for the tool's simplicity.

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?

Given zero parameters, no output schema, and the readOnly annotation, the description covers everything an agent needs: what it does, what it checks, and when to use it. Nothing critical 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?

The tool has zero parameters, so the baseline is 4. The description doesn't need to explain parameters, and it correctly implies the tool takes no input.

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 states a clear verb and resource ('checks internet connectivity') and enumerates the specific checks (gateway reachability, DNS, captive-portal). It also signals the primary use case ('Start here when the user reports the internet is down'), which distinguishes it from sibling tools like get_dns_status or get_connection_status.

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?

It explicitly says 'Start here when the user reports the internet is down', giving a concrete scenario. It doesn't explicitly mention when not to use it or point to alternatives, but the directive is sufficient for a zero-parameter diagnostic tool.

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