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

Annotations already cover readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false. The description adds real behavioral context beyond that: the call yields a hand-off link into Stripe's own hosted flow where the actual mutations happen, and that flow supplies confirmation and audit semantics the agent shouldn't reimplement.

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 tight sentences, front-loaded with what it returns, then what it's for, then the routing preference. No restatement of the name/title and 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?

For a single-optional-param tool with an output schema, the description covers purpose, usage preference, and the key behavioral fact that the real work happens in Stripe's hosted flow. Return-value details are rightly left to the output schema; only the redirect_url's behavior on the hand-off is unaddressed.

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% and the single optional redirect_url is already documented in the schema as 'Where Stripe returns the user afterwards.' The description adds no format, validation, or fallback guidance for it, so the baseline 3 applies.

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+resource ('Get a Stripe billing-portal link') and immediately pins the scope to the 'connected company.' The second sentence clarifies what the returned link is for (plan changes, card updates, invoice downloads, cancellation), which separates it from generic link/mutation siblings.

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 an explicit routing rule: prefer this over performing plan/card/invoice/cancel actions through other tools, with a reason (Stripe's confirmations and audit trail). It stops short of naming when NOT to use it (e.g., vs. create_checkout_link for first-time purchases), so it is strong context without full exclusions.

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