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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds genuine behavioral context by disclosing an embedded assumption ('closing costs are the page's 3% estimate') and the time basis of inputs, though it does not cover defaults, error behavior, or how missing optional inputs are handled.

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?

Three compact sentences with the core function front-loaded, followed by output list and assumption/unit notes. Every sentence carries information, though the unit sentence is partly redundant with the schema.

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 usefully enumerates the computed results and flags the 3% closing-cost assumption. For a 10-parameter calculator it is reasonably complete, though it omits which optional inputs have defaults and how the two undocumented parameters (purchase, intPct) are interpreted.

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 coverage is 80%, so the schema largely documents the parameters. The description's unit notes ('taxes and insurance are annual; maintenance is monthly') restate what the schema descriptions already say, and it adds nothing for the two undocumented parameters (purchase, intPct). 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?

The description names a clear verb+resource ('Cash flow analyzer') and enumerates the specific outputs (itemized P&L, cap rate, gross yield, cash-on-cash, break-even occupancy), so an agent knows exactly what it computes. It fails to differentiate from siblings like calculate_cap_rate and calculate_gross_yield, which compute overlapping metrics, so it stops short of a 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?

There is no guidance on when to use this tool versus the many overlapping siblings (calculate_cap_rate, calculate_gross_yield, calculate_opex, calculate_dscr). The purpose implies it is a full underwriting calculator, but the description gives no conditions, prerequisites, or alternatives to route the agent correctly.

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