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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is covered. The description adds non-obvious behavioral context beyond that: a referential-integrity precondition that will cause the call to fail. It stops short of stating irreversibility or what the failure/response looks like, but it meaningfully enriches the destructive semantics.

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?

Two sentences, no filler, and the operation is front-loaded before the constraint. Every clause earns its place by either naming the action or the failure condition.

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 an output schema present and annotations covering the destructive/idempotent profile, the description supplies exactly the missing piece an agent needs before calling: the in-use blocking rule. Nothing required to invoke this correctly is absent.

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 parameter 'id' is already documented as coming from list_payment_methods. The description adds no parameter-level detail, so the baseline of 3 applies — the schema does all the work.

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?

Specific verb (Deletes) plus specific resource (payment method), with the affected entity clearly named. It is trivially distinguishable from the other delete_* siblings (delete_category, delete_record, delete_recurring_expense) because the resource is stated in the first three words.

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 blocking condition and remediation path: the tool is refused while any record still references the payment method, and the agent should reassign or delete those records first. This is real when/when-not guidance, though it does not name a sibling tool (e.g., update_payment_method) as the alternative for the reassignment step.

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