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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, so the safety profile is covered; the description adds genuine value by disclosing a per-call cost of 1 credit, which is not in any structured field. It says nothing further about output shape, limits on text size, or language handling, so it stops short of rich behavioral context.

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?

A single compact fragment that front-loads the metrics and appends the cost in parentheses, with no filler. It is telegraphic rather than a full sentence, but every token carries 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 one-parameter, no-output-schema tool, the description effectively doubles as an output summary by listing the metrics returned, which compensates for the absent output schema. What is missing is modest: no usage context and no input constraints, but annotations carry the safety profile.

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 coverage is 100% and there is only a single required-by-semantics 'text' parameter, so baseline is 3. The description adds no meaning about the text parameter itself (size limits, expected language, plain vs. markup) beyond what the schema states.

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 enumerates the concrete outputs (word/sentence/paragraph counts, reading time, Flesch reading ease, top words), which makes the tool's function unambiguous even though it uses a noun phrase rather than an explicit verb+resource. It does not need sibling differentiation here, since hash_text and the other siblings are clearly unrelated utilities.

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?

There is no when-to-use or when-not-to-use guidance, no mention of alternatives, and no prerequisites or input constraints. The agent must infer that this is a pure computation tool to be called on arbitrary text.

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