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

Goes well beyond the annotations (readOnly=false, destructive=false, idempotent=false) by explaining the anonymous-vs-signed-in split: unsigned calls return a claim link and work immediately, signed-in calls save to the account and allow a custom ending. This auth/precondition detail is exactly the context the annotations cannot carry.

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?

Front-loads the core action in the first sentence and keeps behavioral detail in the following two. Slightly repetitive around the signed-in/not-signed-in distinction, but every sentence contributes and 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 4-param creation tool with no output schema, it covers purpose, triggers, auth preconditions, and even the shape of the response (a claim link). Only the exact return payload beyond the claim link is left unstated, which is a minor gap.

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 adds usage-level context for the optional parameters — title, domain, and ending all require a signed-in account (and domain requires a plan with own domains). That precondition framing is more useful than the terse per-field schema text.

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 ('Turn a long web address into a short snip.link link') and adds the QR-code byproduct. Clear enough to distinguish from list_links/delete_link, but it never explicitly differentiates itself from make_qr_code, which it partially overlaps with.

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 concrete triggers: 'when the user wants a short link, a link they can change after printing, or click and scan counts.' That is clear when-to-use context, though it names no alternative tool (e.g., update_link) and states no when-not-to-use condition.

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