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

Goes far beyond the annotations (readOnly/idempotent/openWorld) by disclosing what gets sent to the index ('picked sentences go to the index as quoted queries'), latency (3-15 s, 3 concurrent searches), price (USD 0.08, no free tier), error semantics (422 for no 8+ word sentence, 503/504 not charged), index limitations (Mojeek sample, absence is not proof of originality), and an explicit untrusted-data/prompt-injection warning. This is unusually complete behavioral disclosure.

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?

Purpose is front-loaded in the first sentence and nearly every clause carries usable information (cost, timing, errors, caveats). It is nonetheless a dense single-block paragraph with several semicolon-chained facts, and a couple of items (equal price for max_sentences) restate schema content, so structure could be cleaner.

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?

With an output schema present the description need not explain return fields, yet it still sketches them (share_found, sources ranked by sentences held), and it covers cost, latency, error codes, index caveats, and prompt-injection safety. Nothing material for a correct, well-interpreted call 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%, so the schema already documents text length, the 8+ word sentence rule, max_sentences bounds and equal pricing, and exclude_domains. The description adds only the behavioral note that picked sentences are forwarded as quoted queries, not additional parameter meaning; baseline 3 applies.

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 resource ('Check a text for copied sentences: web pages that contain them word for word') and the exact scope of the check (exact-phrase search over the text's most distinctive sentences). It also distinguishes itself from the sibling web_search, so an agent can route correctly without opening the schema.

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?

Explicitly names the alternative and condition: 'For a general query use web_search,' and warns this is not a general search. It further clarifies what the tool does NOT deliver ('No verdict on who or what wrote it') and how to read negative results, which is actionable usage context, though it does not spell out when the tool should be skipped entirely (e.g. short texts).

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