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

The description says the tool 'Create[s]' a link, i.e. produces a new resource and charges $0.003 USDC, while the annotations declare readOnlyHint=true (no environment modification). A paid resource-creating call marked read-only is a direct contradiction that could lead an agent to invoke it as a free, side-effect-free read.

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 front-loaded sentence with the verb and resource first, followed by duration, click-tracking, safety screening, and cost. Every clause carries information an agent needs; nothing is padding.

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 2-parameter tool with no output schema, the description covers cost, safety checks, duration bounds, click counting, and the result URL shape. It stops short of stating URL format requirements, failure behavior, or payment/x402 prerequisites.

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 compensate. It supplies real meaning for 'days' (1-365 range) and tells the agent what 'url' is checked against, but never specifies the required URL format (scheme, length) or what happens when 'days' is omitted.

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 ('Create a short link'), gives the output shape (agentrxi.com/r/...), the validity window, and the safety pre-check. An agent can immediately tell this apart from siblings like url_unshorten or links_check.

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?

No explicit when-to-use/when-not guidance and no named alternative (e.g., url_unshorten for the reverse direction). However, it does state prerequisites and constraints (1-365 days, malware/phishing screening, per-call cost) that implicitly frame when the tool is appropriate.

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