Detect local apps

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

Annotations already declare read-only, idempotent, non-destructive, and closed-world, and the description still adds substantial context: operations are credential-free and bounded, redirects are never followed, non-loopback addresses are never probed, and results exclude auth/health verification. That is above and beyond the structured hints.

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?

Three tight sentences, zero filler. The core capability is front-loaded and each following clause adds a distinct boundary or output note.

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?

With an output schema present, return values need not be explained, yet the description still notes that confidence and already-registered services are returned. Safety profile, scope restrictions, and limits are all covered.

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 takes zero parameters, so the baseline is 4; there is no parameter surface for the description to clarify. Schema coverage is listed at 100%, leaving nothing to compensate for.

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 and resource ('Discover local listening TCP services') plus the mechanism ('credential-free, bounded loopback HTTP fingerprints'). No sibling tool in the list does local service discovery, so the agent can select it unambiguously.

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 bounds behavior clearly (no redirects, no non-loopback probes) but gives no explicit when-to-use framing or routing to alternatives such as 'health' or 'doctor' for verification tasks. Usage is implied rather than stated.

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