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

With no annotations, the description carries the full burden, and it does disclose two valuable traits: default range of trailing 7 days and a monetization rule (first report free per operator, then subscription). It says nothing about the report contents, latency, or what failure looks like when no subscription exists.

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, front-loaded with the resource and range, with the billing caveat trailing. The curly-brace notation is terse but not wasteful; every clause carries information.

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 two-param, zero-required tool with no annotations and no output schema, the description covers parameters and cost but leaves the agent guessing about the report's contents and the behavior when the free quota is exhausted.

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 coverage is 0% (bare numeric types only), so the description must compensate, and it does: it names both parameters, gives the unit (epoch seconds), and states the default when omitted. Required-count is zero, consistent with the described defaults.

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 resource and output shape: a weekly roll-up over a start/end range. It does not mention how it differs from siblings like account or verdict, so it falls short of the 5 bar, but an agent can still tell what it produces.

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: the weekly cadence and the 'defaults trailing 7 days' behavior suggest when it fits, and the billing note hints at a precondition. Nothing tells the agent when to prefer this over another tool, or what happens if the operator's free report has already been used.

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