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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is fully covered. The description adds that it 'counts exactly, which assistants often get wrong' — a useful reliability claim — but discloses no return format, character-limit behavior, or how missing keywords are handled. With annotations carrying safety, this is adequate but not rich.

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 tightly-packed sentences: first enumerates the metrics front-loaded, second makes a single credibility point. No filler, no repetition of the title.

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 analysis tool with full schema coverage and no output schema, the description is nearly complete — it lists all outputs an agent would need. Minor gap: it doesn't state that secondary_keywords are optional or that missing keyword just omits that section, though the schema implies optionality.

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%, so the schema does the heavy lifting and baseline would be 3. The description adds meaning beyond the schema by explaining what 'keyword' placement and density are computed against and implying secondary_keywords are counted alongside the focus keyword. Slight credit above baseline for clarifying the focus-keyword concept.

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 the exact resource (pasted text) and enumerates the specific metrics produced: word/sentence/paragraph counts, reading time, Flesch ease, long sentences/paragraphs, headings, and focus keyword count/density/placement. It's clearly distinguishable from sibling tools like meta_tags_builder or seo_roi, which do different SEO work.

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 description makes usage implied by stating 'Analyses text the user pastes' — this signals it's for user-supplied content rather than URLs. However, there's no explicit when-to-use vs. alternative guidance, such as distinguishing it from acos_check or other content-related checks, and no stated exclusions.

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