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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so safety behavior is covered. The description adds substantial behavioral context beyond annotations: the default date range for rates, what each view returns conceptually, and the fact that agreement and savings depend on IDs and month. It does not discuss pagination or limits, so not a 5.

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?

The content is dense and largely free of fluff, and the first view is front-loaded. But the entire description is one long run-on sentence with nested parentheticals, making it harder to parse than a structured list of views and their parameters would be.

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?

Given the tool's complexity (7 optional parameters and 5 views) and the presence of an output schema, the description is largely complete: it explains each view and maps most parameters to the right view. It is not fully complete because it does not explain the state enum meanings or explicitly state which parameters are required for agreement and savings views.

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 burden. It successfully maps start/end to rates (including YYYY-MM-DD format and the last-30-days default), state to agreements, agreement_id to agreement, and baseline_id plus month to savings. The main gap is that the state enum values (act/watch/clear/off) are not explained.

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 clearly states that the tool views vendor cost data and enumerates five distinct views (rates, agreements, agreement, baselines, savings) with what each contains. It does not differentiate this tool from sibling tools such as get_savings, seats, or list_bills, so it stops short of 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?

It gives explicit usage context for the rates view ('use before saying a vendor overcharged or whether a deal is good') and implicitly maps parameters to other views. However, it never names alternatives or says when to use this tool instead of siblings like get_savings or list_bills, leaving most when-to-use guidance implied.

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