parse_url

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

With no annotations, the description carries the behavioral burden and does so well: it discloses that it reports scope 'without contacting it' (no network side effects), and states cost/rate profile ('free, no quota, instant'). Remaining gaps — behavior on malformed input, error semantics — are modest and largely covered by the output schema.

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 sentences, front-loaded with the core action, then the specific detections, then the usage cue and cost note. No redundancy and every clause carries decision-relevant information.

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, single-parameter analyzer with an output schema, the description supplies everything an agent needs: what is detected, that scope is checked, that no network call occurs, and that there is no cost. Return-value details are correctly delegated to the output schema.

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 there is a single required 'url' parameter, so the schema already documents the input. The description adds only indirect framing ('any suspicious link') and no format or encoding guidance beyond what the schema provides, warranting the baseline 3.

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+resource ('Break a URL into its parts') and enumerates the exact anomalies it detects (userinfo before host, double percent-encoding, backslashes, non-canonical hosts). This clearly separates it from fetch/lookup siblings like http_fetch and dns_lookup, which act on the network rather than analyzing the string.

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?

'Use this on any suspicious link before deciding to fetch it' gives a clear trigger condition and positions it ahead of http_fetch in the workflow. It stops short of explicit exclusions (e.g., when to skip parsing and go straight to a lookup), so it is strong context rather than a complete routing rule.

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