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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is covered. The description adds that output is 'directional' and a range rather than a point estimate, which is useful, but it says nothing about precision, assumptions, or how inputs must be bounded.

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 functional sentence is tight and front-loaded, but roughly half the description is a promotional URL to an external site, which consumes space without helping the agent invoke the tool correctly.

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-value burden; it does name the two outputs (ARR multiple, enterprise value range) but does not say what form they take or how to interpret 'directional'. Adequate but with clear gaps for a calculator 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%, so all four parameters are already documented in the schema. The description echoes growth, NRR and margin (and implicitly ARR) without adding unit, range or format constraints beyond what the schema states, so 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?

Specific verb (Estimate) plus a precise deliverable (directional ARR multiple and enterprise value range) and the three input drivers. It is clear what the tool does, but it never distinguishes itself from the very similar sibling arr_multiple_calculator, so an agent must guess which is the right entry point.

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?

There is no statement of when to use this tool, what conditions make it appropriate, or which sibling (arr_multiple_calculator, rule_of_40_sandbox) it replaces. The only routing hint is a link to a web calculator, which is not guidance for an agent.

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