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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds important behavioral context: 'No credits spent, no I/O' and a pricing model. It does not mention auth requirements or rate limits, but the added side-effect clarity is valuable.

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 short sentences, front-loaded with the core purpose and pricing formula. Every sentence adds useful information without waste.

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?

The tool has an output schema, so return values need not be explained. The description provides the base cost, key adjustments, and no-side-effect assurance. It is nearly complete, though it does not fully document all exclude enum values or default parameter behavior.

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 partially compensates by explaining that excluding 'ai-ugc' saves 5 credits and server-side render adds 3. It does not explain the full exclude enum or default behavior for either parameter, leaving gaps.

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 (estimate) and resource (credit cost of snack generation) with clear scope (before running it). It distinguishes this tool from generation siblings like generate_snacks by emphasizing estimation rather than execution.

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 phrase 'BEFORE running it' clearly signals when to use the tool: prior to generation. However, it does not explicitly name alternatives or state when-not to use it, leaving the routing to inference from sibling names.

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