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

Annotations already declare readOnly, idempotent, and non-destructive, so safety is covered. The description adds real behavioral context beyond that: results depend on whether a key is supplied (account measured/estimated totals vs community verified totals), and it warns that 'Unmeasured is not zero', preventing a misinterpretation of the data.

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 dense sentence that is front-loaded with the core resource and keeps the most decision-relevant caveat ('Unmeasured is not zero') at the end. It is efficient, though the ambiguous 'with a key' clause costs some clarity.

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 characterizes the return content (measured, estimated, or community verified totals) and flags the unmeasured-value pitfall. What remains thin is the meaning of the single input parameter and how authentication changes behavior.

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 0%, so the description must carry the param, and it only partly does -- it conveys that 'model' scopes results to a single model but never states the expected format or identifier semantics. The 'with a key' phrasing further muddles whether the parameter or credentials control the mode.

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 the resource (savings totals) and the scoping option (one model), so the agent knows it retrieves savings figures. However, the clause 'with a key' is cryptic -- it never says whether 'key' means the model parameter or authentication -- and it does not distinguish this tool from the sibling report_savings.

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?

It implies the model parameter is optional ('optionally for one model') but gives no guidance on when to call this versus report_savings or the other siblings. There are no stated prerequisites or exclusions, so the agent must infer usage from the name alone.

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