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

With no annotations at all, the description still discloses two traits the schema does not: the price (0.001 USDC per call via x402) and the shape of the result (parsed components plus a cleaned URL with tracking params flagged), which matters because there is no output schema. It stops short of covering failure behavior for malformed or relative URLs and does not clarify whether the cleaned URL is returned alongside or instead of the raw one.

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, both earning their place: the capability and its outputs come first, the pricing constraint second. No filler, no restatement of the tool name, and the most decision-relevant content is front-loaded.

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 2-parameter, single-purpose parsing tool with no annotations and no output schema, the description covers the essential ground: what comes back and what it costs. The remaining gap is edge-case behavior (invalid or relative URLs, exact form of the cleaned URL), which is minor but non-zero for a tool that must handle arbitrary user-supplied strings.

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% — 'url' is documented as an Absolute URL and 'paymentProof' carries a full two-step 402 flow explanation. The description adds no parameter-level detail beyond that, so the baseline of 3 applies; it correctly mirrors the payment model without extending it.

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 (splits) plus the exact resource (a URL) and enumerates the returned components: protocol, host, port, path, query params, fragment. It also names a secondary capability (tracking-parameter flagging with a cleaned URL), which no sibling like web_extract or http_check provides, so the agent can distinguish it without opening the schema.

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 implied by the purpose — an agent can infer this is the tool for decomposing a URL string — but the description never says when to pick it over neighbors such as web_extract or http_check, nor does it state any exclusions. There is no explicit when/when-not guidance, so this sits at the minimum-viable level.

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