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

Annotations already declare this a safe, non-destructive, closed-world read, so the description only needs to add context. It does add real value by disclosing the computation (rated range times battery %) and the monthly aggregation, but says nothing about history depth or how sparse data is handled. The 'estimated' qualifier usefully warns that values are derived rather than measured.

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?

A single sentence with the metric, its derivation, and its granularity front-loaded; no filler, no redundancy.

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 one-optional-parameter read tool with annotations covering safety, this is close to complete, but with no output schema the description should say what a result looks like or how far back the monthly series extends. It leaves the agent guessing about time span and data availability.

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% and the vin parameter already documents the multi-car requirement, the last-4-6 shortcut, and the list_vehicles-first instruction. The description adds nothing about vin, 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?

Names a specific metric (estimated range at 100% charge) plus its derivation (rated range and battery %) and granularity (by month), so an agent can tell it apart from tire_pressure_trend or get_history. It stops short of explicitly excluding the raw-history sibling, which would have made it 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?

Usage is only implied: an agent can infer this is the tool for tracking battery degradation over time. There is no explicit when-to-use statement, no exclusion of alternatives like get_history, and no note on prerequisites such as needing months of data.

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