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

No annotations exist, so the description carries the full disclosure burden. It reveals two useful traits — the 15% default tip and a per-call price of $0.001 (USDC, eip155:8453) — but says nothing about rounding, currency assumption, or error behavior. It also conflicts mildly with the schema, which marks tipPercent as required, undercutting the 'defaults to 15%' claim.

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?

One tight sentence front-loads the core operation and outputs; nothing is wasted. The appended pricing string is relevant but stylistically detached from the calculator description.

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?

With no output schema, the description must carry the return contract, and it does list the three outputs. However it omits rounding/precision, currency, and the tipPercent-required discrepancy, leaving gaps for a three-parameter tool.

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 100% for all three parameters (bill, tipPercent, people), so baseline is 3. The description adds only the tip default and the split semantics, without clarifying units or edge cases beyond the schema.

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?

States a specific verb and resource (tip for a bill) plus the derived outputs (grand total, per-person split), which cleanly separates it from sibling calculators like vat_calculator, discount_calculator, and loan_payment_calculator. An agent can identify the operation without opening the schema.

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 never says when to pick this over the many adjacent calculators in the family, nor any when-not condition. Only the 15% default hints at intended usage; there is no routing guidance at all.

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