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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered; the description's main added value is the authorization constraint that only the account owner can open the link and that teammate keys are refused. The closing clause 'Reading changes nothing' largely restates readOnlyHint, and no rate-limit or link-expiry behavior is disclosed.

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 well-formed sentence, front-loaded with the verb and resource, then purpose, then the access restriction. The only expendable clause is 'Reading changes nothing', which duplicates the readOnlyHint annotation.

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 zero-parameter, read-only lookup with an output schema, an agent needs only to know what the link points to and who may call it — both are stated. Failure behavior for non-owner keys is explicitly described, so nothing material is missing.

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 there is nothing beyond the schema to explain and the description correctly spends no words on arguments. Its silence on parameters is appropriate rather than a gap.

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 ('Get the address of the account's billing page on the website') and immediately clarifies what that page is for. It is clearly distinguishable from siblings such as get_share_link or get_payment_record, which return different kinds of links or records.

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 the operative usage condition: the caller must be the account owner, and a teammate's key is refused. What it does not do is route the agent elsewhere for non-owner cases (e.g. to get_share_link or get_payment_record), but no sibling offers an equivalent billing-page alternative, so the omission is minor.

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