estimate_agent_cost

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behaviors: returns a comparison table with costs per call/run/day, includes optimization tips and pricing guidance, and specifies that no API key is needed. This covers output format and authentication requirements well, though it could mention rate limits or error handling.

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?

The description is efficiently structured: first sentence states the purpose, next describes the output, then notes key features, and finally details parameters. Every sentence adds value with zero waste, making it easy to scan and understand quickly.

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 the tool's complexity (cost estimation across models) and the presence of an output schema, the description is complete. It covers purpose, output format, key features (no API key needed), and all parameters. With an output schema handling return values, no additional explanation of outputs is needed in the description.

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 description coverage is 0%, so the description must compensate. It adds significant value by explaining all 5 parameters in the Args section, providing examples (e.g., 'claude-sonnet-4') and clarifying their purposes (e.g., 'Estimated input tokens per call'). This goes well beyond the bare schema, though it doesn't detail constraints like token ranges.

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 the tool's purpose: 'Estimate the cost of running an agent task across all major models.' It specifies the verb 'estimate' and resource 'cost,' and distinguishes itself from siblings like check_usage or buy_credits by focusing on cost estimation rather than usage monitoring or purchasing.

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 provides clear context for when to use this tool: for estimating agent task costs across models. It mentions 'No API key needed,' which is helpful guidance. However, it doesn't explicitly state when NOT to use it or name specific alternatives among siblings like check_usage for actual usage data.

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