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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered by structured data and the description needn't repeat it. However, the description contributes nothing beyond that — no mention of what assumptions the calculation makes, whether results are nominal or inflation-adjusted, or what the response contains, despite there being no output schema.

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?

It is short, but brevity here is under-specification rather than conciseness. The one meaningful clause ("FIRE calculator") is followed by a vendor tag that earns no place in the text and crowds out the units/format guidance an agent actually needs.

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?

A 5-parameter financial calculator with zero schema descriptions, no output schema, and no annotations covering calculation semantics. The description does not state input units, whether percentages are expressed as whole or decimal numbers, or what the returned figure represents — an agent cannot reliably invoke this from the definition alone.

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 0% across 5 numeric parameters, and the description supplies no compensating information. An agent gets no hint that annualSpend is currency, that expectedReturnPct and withdrawalRatePct are percentages (e.g., 7 vs 0.07), or how annualContribution relates to currentSavings — all of which are essential to calling this correctly.

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 phrase "FIRE calculator" does identify a rough resource type (financial independence / retire early projection), but there is no verb describing what the tool computes or returns. The trailing clause "client and server side from freedailypro" is opaque vendor boilerplate that adds no distinguishing meaning versus siblings like converters_401k or calculate_compound_interest.

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?

No when-to-use guidance whatsoever. With a large sibling family of converters_* financial tools (401k, 529, RMD, social security), the description does nothing to help an agent choose this FIRE projection over those alternatives, nor does it state prerequisites or exclusions.

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