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

Annotations already declare readOnly, idempotent, closed-world, non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: the 120-month search horizon, that month 1 is the current month, that it mirrors a specific web calculator's math, and that defaults align with the web version – all useful for interpreting results.

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?

Output list is front-loaded and dense, with the reference URL and horizon packed into a short block. Slightly overloaded by enumerating seven outputs in one run-on, but no sentence is wasted.

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?

For a 9-parameter, all-optional projection tool with no output schema, the description carries most of the load by naming the return metrics and the time horizon. It falls short only on how the two overrides change results and on the units/interpretation of 'default alive or dead', leaving a small gap.

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 100%, so every parameter including the two overrides is already documented in the schema. The description adds only the framing that growth rates drive projections and that overrides exist implicitly; it does not explain override precedence or interaction 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?

States a specific verb (projects, month by month) and resource (cash/burn/runway) and enumerates the exact outputs: net burn, runway, zero-cash month, break-even, default alive/dead, burn multiple, and the expense-cut variant. This is precise enough to separate it from siblings like calc_saas_metrics without opening a schema.

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 description implies usage by explaining defaults and that month 1 is the current month, but it never states when to prefer this over calc_saas_metrics or the other finance calculators, nor any exclusions or prerequisites. The 'omit to compute' guidance for overrides is present in the schema, not the description.

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