Usage-based text generation

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is well-covered. The description adds important behavioral context beyond annotations: pricing model (usage-based, max $0.05), which is a critical behavioral trait for an AI agent deciding to invoke this tool. No contradiction with annotations is present.

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, no filler. The first sentence states core purpose; the second adds billing details. Slightly longer than ideal due to the billing explanation but every sentence serves a distinct purpose. Could arguably omit the 'x402...' parenthetical detail without losing essential meaning, but it remains 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 simple 1-parameter generation tool with no output schema, the description covers purpose, pricing, and behavioral constraints well. It doesn't describe the output format or expected length, but that is reasonable given the absence of an output schema and the low parameter count. The annotations compensate for safety concerns.

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% with a single required parameter (prompt) whose description 'Text prompt to generate insights about' is already informative. The tool description adds no additional meaning beyond what the schema provides for this parameter, so baseline 3 is appropriate.

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 starts with a specific verb+resource combination ('Generates short text output for a prompt'), and explicitly notes billing details and a max cost cap ($0.05), which helps distinguish it from sibling read-only tools like get_weather or get_crypto_price. The purpose is immediately clear.

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 explains when to use this tool (for generating short text) and crucially adds pricing behavior ('Billed by output length... max $0.05 per call'). It does not explicitly mention when NOT to use it or name alternatives, but the context of 15+ sibling tools (none doing text generation) makes the usage scope evident.

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