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. The description adds genuine context beyond that: what the opened panel renders and that missing inputs fall back to site defaults. It does not, however, discuss any UI-state or repeated-open behavior, so it stops short of full disclosure.

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?

Four tight sentences, front-loaded with the capability, then the trigger, then parameter guidance, then the alternative. No sentence is redundant and nothing important is buried.

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?

An output schema exists, so return values need no explanation, and the annotations carry the safety profile. The description covers capability, trigger conditions, parameter sourcing, default behavior and sibling routing, which is everything an agent needs to select and invoke it correctly.

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 the nested inputs and oneTimeCosts fields are already fully documented. The description still adds operational meaning by telling the agent to pass the inputs and one-time costs from the scenario under discussion and that omitted inputs use site defaults, which goes slightly beyond the schema baseline.

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 and resource ('Opens an interactive rent-vs-buy calculator') and even enumerates the panel contents (editable inputs, net-worth charts, year-by-year report, Monte Carlo analysis). This clearly distinguishes it from siblings like rentbuy_run_scenario and rentbuy_sweep, which compute without opening a panel.

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?

Gives explicit when-to-use ('when the user wants to see or adjust a scenario') and when-not ('Use the other rentbuy tools for calculations, comparisons and sweeps without opening a new panel'). The routing between opening a panel and running a calculation is unambiguous.

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