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

Annotations already cover readOnly, idempotent, non-destructive, and closed-world traits, so the bar is lower; the description still adds real behavior: the rent-sourcing order (ACS B25031 → HUD FMR) and the failure mode ('The tool does not invent one'). That last line is a genuinely useful disclosure about non-fabrication. It does not explain the calculation behavior for the other cost parameters, keeping it from 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?

It is front-loaded with the purpose sentence, and the remaining sentences each carry substantive information about rent sourcing. The sourcing sentence is long and comma-heavy, but every clause is doing work rather than padding.

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?

This is a 15-parameter financial calculator with no output schema and no annotations describing the result, yet the description says nothing about what the comparison returns or how the ~10 cost inputs affect it. For a tool of this complexity, the coverage of the input surface and output is well short of what an agent needs.

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 15 parameters, so the description must compensate. It only covers nightlyRate, occupancyPct, and monthlyRent (and touches zip/bedrooms via the sourcing logic); the other ~10 cost parameters (hoaAnnual, taxesAnnual, strMgmtPct, ltrMgmtPct, platformFeePct, etc.) are undocumented anywhere. It also refers to 'monthly_rent' while the schema field is 'monthlyRent', a minor naming mismatch.

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 comparison: short-term rental revenue (nightly rate × occupied nights) vs long-term rent. It even defines how each side is computed, which makes the tool's purpose concrete. However, it never differentiates itself from near siblings like estimate_rent, lookup_hud_rent, or calculate_cash_flow, leaving the agent to guess why this tool rather than those.

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 implied usage via the fallback logic ('if you omit it... otherwise... pass monthly_rent'), which tells the agent how to invoke the LTR side under different conditions. But there is no explicit when-to-use or when-not-to-use statement and no comparison against the sibling calculators that also deal with rent.

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