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

With no annotations, the description carries the full burden: it does disclose stopword filtering, deterministic scoring, ngram expansion behavior, and the $0.008 x402 cost, which is genuinely useful context. It omits return format, error/truncation behavior for the 200k-char input cap, and what x402 payment actually requires of the caller.

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 short sentences, front-loaded with the core operation, then the ngram qualifier, then cost. No wasted text, though the telegraphic fragments read more like spec bullets than instructions.

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?

No output schema and no annotations, so the description should ideally describe the returned structure (terms with scores) and payment mechanics. It hints at scores via 'scored multi-word phrases' and does cover cost, but an agent still can't predict the response shape or the x402 flow.

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 0%, so all three parameters are undocumented in structured data. The description partially rescues 'ngrams' ('2-3 adds scored multi-word phrases') but its stated range conflicts with the schema's 1-3, and neither 'text' (200k max) nor 'limit' is explained anywhere.

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 operation ('deterministic term ranking from free text') that maps unambiguously to keyword extraction, and names its defining traits (stopword-filtered, deterministic). Siblings are unrelated single-purpose utilities, so no differentiation is needed, but the description never uses the tool's own verb 'extract' to anchor intent.

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?

No when-to-use guidance, no exclusions, no mention of alternatives. 'Deterministic' faintly implies this is the non-LLM option, but nothing tells an agent when to pick this over, say, seo or token_count.

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