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

Annotations already declare readOnlyHint=true and non-destructive, and the description adds substantial non-obvious context: the exact normalization/truncation algorithm and the x402 billing model with the explicit rule that failed calls are not charged. It omits the truncation length and the capacity/rate limits, which are the remaining behavioral unknowns.

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, tightly front-loaded: purpose first, algorithm second, cost last. Every clause carries information an agent would otherwise have to guess.

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 zero-param transform with annotations covering safety and no output schema needed, the definition is nearly sufficient. Two gaps remain: the truncation target length is unspecified, and with an empty input schema the description never shows where the source text comes from.

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?

Zero parameters, so the schema carries nothing and the baseline is 4. The description compensates by defining semantics the (absent) parameter would have had — separator policy, unicode decomposition, word-boundary truncation — but never explains how the 'arbitrary text' is actually supplied.

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 output (URL-safe slug) plus the exact input class (arbitrary text), then spells out the transformation pipeline. An agent can distinguish this from normalize/hash/redact siblings without opening anything else.

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 narrow purpose makes the usage context inferable, but there is no explicit when-to-use or when-not guidance, and no mention of the semantically adjacent siblings (normalize, redact, chunk) that might also transform text. Nothing misleads; nothing routes either.

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