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

The annotations declare readOnlyHint=true ('does not modify its environment'), but the description states 'Pay for gigabytes of traffic' and 'get a proxy login ... after payment', i.e. a paid purchase that transfers value and provisions a credential. That is an environment-modifying, non-read-only operation, so the description directly contradicts the annotation. The genuinely useful behavioral context it does supply (90-day expiry, stablecoin payment, Base/Polygon only, per-connection rotation) cannot offset a contradiction about whether the tool is mutating.

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?

Five short sentences, each carrying a distinct fact (who it is for, what you get, how to use it, geo/rotation, duration, payment rails), with the core purpose front-loaded. Slightly list-like and abbreviation-heavy ('90 days', 'Not offered on Solana'), but there is no filler.

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 describes the returned artifact (a host/port/username/password login usable with any HTTP client), plus duration, geo options and accepted payment chains. What it omits is the mechanics of payment (how the stablecoin transfer is actually effected) and whether the credential is single-use — meaningful gaps for a commerce tool.

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% – both `gb` and `country` are fully documented, including the byte counting and the per-connection username override. The description's mention of choosing a country and rotating the IP slightly amplifies `country`'s meaning, but the 'session tag' concept it introduces is not a parameter in the schema, so it adds little parameter-level information.

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 makes a generic name concrete: it states that the tool sells a residential proxy pack, charges per gigabyte, and returns a proxy login (host, port, username, password). That is a specific verb-and-resource statement an agent can act on. It does not, however, distinguish itself from the sibling `fetch`, which an agent might assume is the tool for actually routing traffic.

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 context is implied rather than explicit: 'for AI agents' and 'to use with curl, a browser or any HTTP client' tell the agent the downstream purpose, and the choice of country/rotation gives selection guidance. There is no when-not guidance and no mention of how this relates to the `fetch` or `feedback` siblings, so routing between tools is left to inference.

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