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

Annotations already declare a safe, read-only, idempotent calculator, so the description does not need to repeat safety. It adds useful behavioral context by noting that option-pool top-ups happen before each round, which affects how dilution flows through founders. It stops short of explaining the sequence of calculations or the exact result shape.

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?

Two sentences plus an optional link, with the core capability front-loaded and the sibling routing in the second sentence. No sentence is wasted.

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 rich schema coverage and the absence of an output schema, the description is largely complete: it conveys the multi-round model, pool top-ups, and ownership output. It could be stronger by mentioning that results are per round or how existing investors are treated, though the schema covers the latter.

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%, so the schema already defines founders_pct, option_pool_pct, and every round field. The description adds only the high-level notion of pool top-ups before each round; it does not add syntax or detail beyond the schema, so baseline 3 is appropriate.

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 outcome (founder and investor ownership) over a specific scope (several future funding rounds with option-pool top-ups). It clearly distinguishes itself from option_pool and startup_valuation, so an agent can identify the right tool 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?

It explicitly routes single-round pool questions to option_pool and simple single-round valuations to startup_valuation, leaving this tool for the multi-round case. The alternatives and their selecting conditions are named directly.

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