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

Annotations only say readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false. The description adds genuinely useful behavior: the exact artifacts returned, that agent_token is consumed by the other tools, and critically that claim_url is 'sent once; save it' — which is the practical consequence of idempotentHint=false and something an agent must act on.

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?

Three sentences, all load-bearing: the first covers action plus outputs, the second the required language decision, the third the trial/upsell framing. No filler and the most actionable content (claim_url warning) is front-loaded near the start.

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 fully carries the return-value burden: names each returned artifact and flags the one-time claim_url. Combined with the annotation set it covers safety, side effects, and continuation into the sibling tools, leaving no material gap for a 3-param starter call.

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 100%, so baseline is 3, but the description goes beyond it by supplying a selection heuristic for the languages array ('customers most likely speak and say why') and confirming that source_lang is auto-derived when omitted, which shapes how the agent should populate the params.

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 verb and resource ('Set up Proxylang on a website') with the distinctive modifier 'with no signup', and immediately enumerates what the call produces (script tag, install steps, agent_token, claim_url). An agent can tell this apart from proxylang_status/check/next without opening any schema.

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?

Gives explicit decision guidance for the language choice ('If the user named a language, use it; otherwise pick the one their customers most likely speak and say why') and explains the trial continuation path ('list other recommended languages after it'). It stops short of naming when to prefer a sibling tool, so it is clear context without explicit alternatives.

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