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

Annotations already declare readOnlyHint=true, openWorldHint=false and idempotentHint=true, so the safety profile is covered. The description adds the set of computed metrics, which is genuinely useful since no output schema exists, but it discloses no limits, truncation behavior for long text, or error conditions.

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 short sentences plus a URL; the utility is front-loaded in the output enumeration. The opening reading-time anecdote is mild marketing padding but it does tie to one of the tool's actual outputs, so it is not pure waste.

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 simple single-input, no-output-schema tool, enumerating the return metrics in prose fills the gap left by the absent output schema. Nothing critical for invoking it correctly is missing.

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% for the single 'text' parameter, and the schema itself supplies a default and maxLength, so the baseline of 3 applies. The description adds only the framing 'Paste text', which does not meaningfully extend the schema semantics.

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 names a specific resource (word/text analysis) and enumerates the concrete outputs: words, characters with and without spaces, sentences, speaking time and top keywords. It is clearly distinguishable from the numeric-calculator siblings, though it never explicitly contrasts itself with closely related text tools.

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 guidance, no prerequisites, and no mention of any alternative. The phrase 'Paste text for...' implies a usage pattern but leaves the agent to infer the context unaided.

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