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

Annotations already establish read-only, closed-world, non-destructive behavior, so the description correctly doesn't repeat that. It adds the crucial non-obvious traits: a paid call ($0.01 USDC on Base via x402) and the REST route POST /v1/text/analyze. It doesn't cover failure modes (e.g., insufficient payment, oversized text beyond the schema note), keeping it from a 5.

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 sentences, zero filler, front-loaded with the use condition followed by the payment and routing details. Every clause carries information an agent needs.

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 single-param read-only tool with no output schema, the description covers the trigger condition, the analysis dimensions returned, the input constraint (via schema), and the payment/transport requirements. It's only slightly short of complete because it doesn't describe the response shape precisely or error behavior on payment failure.

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?

There is a single parameter with 100% schema description coverage including the 20000-char limit, so the baseline is 4. The description adds no additional parameter meaning beyond what the schema already states.

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 states a specific verb and resource ('deterministic text analysis') and enumerates the concrete outputs (counts, Flesch readability, script mix, top keywords), so an agent knows exactly what it gets back. It doesn't explicitly distinguish itself from siblings like hook_score, which could plausibly overlap on text scoring, so it falls short of a 5.

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?

'Use this when you need deterministic text analysis' gives a clear selection condition, and the enumerated outputs sharpen that context. It names no alternatives or exclusions, so there's no guidance on when to prefer hook_score or translate_check instead.

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