pricing

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

No annotations provided; description handles transparency well by stating 'Always returns immediately — has no side effects and costs nothing.' This discloses the tool's safety and performance traits. No additional behavioral details needed for a simple read-only 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?

Three sentences, front-loaded with the core purpose, then elaborates on contents and careful use. No filler; every sentence adds value.

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?

Given no parameters, no output schema, and low complexity, the description fully covers what the tool does, its return value, and usage context. It explains why and when to use it, making it complete for an AI agent.

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?

No parameters exist, so the description adds value by explaining what the tool returns, effectively covering the tool's semantics. Baseline score of 4 applies as no further param info is needed.

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 clearly states it returns a 'machine-readable pricing menu' listing free vs paid, prepaid, etc. It uses specific verbs and resources, and distinguishes itself from sibling tools like account_balance by focusing on tool pricing, not user balance.

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 advises to 'Call this first to understand what is available and at what cost before using paid tools.' It also clarifies it has no side effects and costs nothing, implying safe to call anytime. Lacks explicit when-not or alternatives, but the guidance is clear.

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