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

Beyond the readOnlyHint/openWorldHint annotations, it discloses billing behavior ($0.002 USDC per successful call via x402 on Base/Solana/Arc, failed calls free), a hidden code-level constraint (seo style truncation enforced in code), per-headline character counts, and a caution that model output should have its claims verified. This is unusually rich behavioral context for a billing-relevant tool.

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?

Front-loaded with the core output, then progressively less critical details (count, caution, limits, pricing). Dense with facts but no filler; the pricing sentence is long but operationally relevant.

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?

An output schema exists, so return values need not be explained, and the description still covers billing, input caps, style constraints, and a reliability caveat. Nothing material is missing for correct invocation.

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 3 baseline applies, but the description adds meaning the schema lacks: that only one style may be used per call and that the seo style is programmatically capped at 60 characters. It also restates the 10,000-character text limit already in the schema.

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 ('up to 10 headlines for a text or topic') plus the exact output variants ('news, seo, social or email subject') and inbound limits. No sibling in the text_* family generates headlines, so there is no ambiguity to resolve.

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 implies the usage context (generate headlines from a text or topic, pick exactly one style) and gives style-level guidance, but never states when to reach for this tool versus something like text_outline or text_keywords, nor any prerequisites. Usage is inferable rather than stated.

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