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

Annotations already declare this a safe, idempotent, non-destructive read. Beyond that, the description discloses the 2-10 scenario bound, that deltas are computed against the first scenario (an ordering-dependent behavior), and that each scenario is independent overrides on top of site defaults. Nothing contradicts the annotations.

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 sentences, front-loaded with the operation and its return shape, then the scenario model, then the sibling routing. The enumeration of return fields is somewhat dense but each item is informative rather than filler.

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 an output schema present, the description need not explain return values, yet it still conveys the key ones. It covers cardinality limits, override semantics, delta baseline, and naming. The only minor gap is that the 40-character name limit and the 20 one-time-cost cap live only in the schema.

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?

Top-level schema description coverage is 0% for the single 'scenarios' parameter, but the description compensates by explaining the structure (independent input overrides plus one-time costs layered on site defaults) and the required 'name' semantics with concrete examples. The nested field-level docs are strong, so this adds rather than duplicates.

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 (runs 2-10 named scenarios side by side), enumerates the outputs returned, and explicitly differentiates from the sibling: 'One call replaces many rentbuy_run_scenario calls.' An agent can distinguish it from rentbuy_run_scenario and rentbuy_sweep purely from the text.

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?

Names the alternative it supersedes ('One call replaces many rentbuy_run_scenario calls') and gives practical naming guidance tied to the scenario-override model. It stops short of explaining when NOT to use it (e.g., when rentbuy_sweep's parametric ranges are the right tool instead of discrete named scenarios).

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