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

Annotations already declare readOnly/idempotent/non-destructive, so safety needs no restating. The description goes beyond them by enumerating the computed results (discounted sale price, fees, net proceeds, gain over cost basis, implied valuation), which is the main behavioral thing an agent needs since there is no output schema. It says nothing about unit assumptions or error cases, so not a 5.

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 front-loaded sentence that lists outputs, plus one short reference link – no filler. It is a slightly dense run-on list, but every clause carries real information.

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 correctly spends its words describing the return values, and all eight parameters are documented in the schema. Missing only minor context: that shares_sold is the sole required input and which inputs are conditioned on the other (valuation basis).

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 every parameter including the price_basis enum is already documented. The description only echoes a few field concepts (discount/premium, fees, cost basis) without adding syntax or cross-parameter rules such as valuation basis requiring fully_diluted_shares. Baseline 3 applies.

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?

Opens with a specific verb+resource ("Proceeds from selling private company shares on the secondary market") and enumerates exactly which quantities it computes, so an agent can tell this is a proceeds/gain calculator rather than a valuation or dilution tool. It does not name a sibling it differs from, keeping it just short of 5.

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 "selling private company shares on the secondary market" implies the situation, and the trailing link points to a richer interactive version. But there is no explicit when-to-use/when-not guidance and no mention of adjacent siblings like startup_valuation or dilution that an agent might otherwise pick.

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