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

Annotations already cover safety (readOnly, idempotent, non-destructive), and the description adds context annotations cannot express: a per-call price ($0.002 USDC via x402 on Solana) that is only charged on success, plus an equivalent HTTPS endpoint. It also discloses the benchmark thresholds used for health ratings, which frames the output. It stops short of describing error behavior for invalid inputs.

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?

Front-loaded with the computed metrics, then audience, then price and alternate endpoint. Dense but every clause carries information; the pricing/endpoint sentence is slightly bolted-on but is genuinely useful transaction context.

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 compensates by enumerating the returned metrics and the benchmark logic behind health ratings, which is the key thing an agent needs to interpret results. The 8-parameter surface with only 2 required is left somewhat implicit (which optionals unlock which outputs), a minor gap.

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 88%, so the schema already explains nearly every parameter. The description adds no parameter-level meaning (e.g. how monthlyChurnPct drives average lifetime, or when to supply cashBalance/monthlyFixedCosts for runway and break-even). Baseline 3 is appropriate given the schema does the heavy lifting.

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 concretely what the tool computes: margin-adjusted LTV, LTV:CAC, CAC payback, average lifetime, MRR/ARR, break-even customers, cash runway, with benchmark health ratings. No sibling tool in the list covers this domain, so no disambiguation is needed and the enumerated outputs make the purpose unmistakable.

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?

It names an audience ('startups, API businesses and agent services'), which implies when the tool fits, but never states prerequisites, when-not-to-use, or how it relates to adjacent finance tools like npv_irr, compound_interest or portfolio_metrics. Usage must be inferred from the audience sentence.

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