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

No annotations are provided, so the description carries the full behavioral burden. It discloses a payment/auth trait (5 free trial calls per signed wallet), which is useful, but omits everything else: what counts as a sentence-ending mark ('.', '!', '?', ellipsis?), the return shape, and whether it handles edge cases like abbreviations.

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?

A single front-loaded sentence that wastes little space; the emoji/trial note is the only slightly promotional addition. Efficient overall.

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 two-parameter tool with no annotations, no output schema, and an ambiguous parameter pair, the description does too little. An agent cannot confidently determine which parameter to populate or what the tool returns.

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 0% and there are two undocumented string parameters ('text' and 'input') with no required fields. The description mentions counting 'in text', hinting at the 'text' parameter but leaving the duplicate 'input' parameter and the required-vs-optional behavior entirely unexplained.

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+resource ('Counts sentence-ending punctuation marks in text'), which is clearer than the bare name and explains the counting mechanism. However, it does not distinguish itself from siblings like x402-sentence-split, x402-sentence-case, or x402-avg-sentence-length, which an agent must differentiate.

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 indication of when to use this versus the other sentence-related tools, and no prerequisites or exclusion conditions. The only usage-adjacent signal is the pricing note about free trial calls, which is not guidance about task selection.

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