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

The description goes well beyond the readOnlyHint/destructiveHint annotations by disclosing the $0.08 per-call cost, accepted payment rails, premium key header, unpaid-call offer behavior, and no-charge-on-invalid-input policy. It also states that the tool returns 'scores only, no prices,' which is a meaningful behavioral constraint.

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 long but information-dense: every clause adds value from pricing to payment, error behavior, alternative, and source. It is front-loaded with the core function and paid status. It could be slightly better structured with bullets or shorter clauses, but it is not bloated.

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 single documented parameter, the existing output schema, and the annotations, the description covers all operational essentials: what the tool computes, what it costs, how payment works, what happens on unpaid/invalid calls, and a free alternative. No critical calling context is missing.

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% and the portfolio parameter already has descriptions. The description adds useful semantic context by specifying allocation-weighted scoring and the portfolio-level TVR Score, which clarifies how the single parameter is interpreted. This is more than the schema alone provides.

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 names a specific verb-resource pair and enumerates the exact output: allocation-weighted scores for 8 metrics, per-holding TVR Score and valuation category, and the portfolio TVR Score. It also distinguishes itself from compare_coins as a free alternative, so an agent can separate it from siblings.

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 clearly labels the tool as paid, states the payment methods, and names compare_coins as the free alternative. It also notes that invalid input is refused before payment, which is useful guidance. However, it does not explicitly say 'use this when you need portfolio-level aggregate scores' or articulate exclusions beyond the free alternative.

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