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

Annotations already declare this a read-only, idempotent, non-destructive, closed-world operation. The description adds genuinely useful context beyond that: it is count-only, never exposes creator identity (a privacy guarantee), is scoped to approved creators and posts currently on sale, and classifies coverage as strong or thin.

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 that front-loads the core meaning (network reach to your own audience, per channel) and appends the key qualifier (counts only, no identity). It is dense and a little run-on, but there is no wasted sentence.

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 input parameters and no output schema, the description has to carry the return semantics, and it does reasonably: per-channel counts, a strong/thin coverage signal, and an explicit privacy constraint. The exact shape of the result (e.g., what a channel entry looks like) remains unspecified, which keeps it from a 5.

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?

The tool takes zero parameters, so the baseline for this dimension is 4. Nothing in the description is needed to disambiguate inputs, and it does not introduce any confusing parameter-like language.

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 explains that this reports how well the network reaches your own audience, per channel, as counts, which is a coherent resource. However, it never states a verb ("returns", "reports") and the name/title mismatch ("inventory" vs "Network coverage") plus the lack of any contrast with siblings like resolve_audience leaves the exact purpose somewhat vague.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives. The closest sibling, resolve_audience, is not referenced even though both concern audience reach, leaving the agent to guess which to call.

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