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

Annotations already flag destructiveHint and idempotentHint, so the safety profile is partly covered; the description nonetheless adds genuinely new behavior: the action is permanent ('for good') and previously generated invoices survive untouched. 'Free' conveys a cost/plan detail absent from annotations, though its meaning (no charge vs. free plan) is not disambiguated.

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 very short sentences, front-loaded with the action and its permanence, then the side effect on existing invoices. 'Free.' is a fragment whose meaning is ambiguous, which is the only wasteful element.

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-parameter destructive mutation with no output schema and annotations covering safety, the description supplies the two things an agent most needs: irreversibility and what happens to dependent records. It stops short of covering recoverability (any undo/restore path) or what the call returns.

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?

Only one parameter and schema coverage is 100%, with the schema itself pointing at invoices_list_repeating as the source of repeating_id. The description adds nothing about the identifier beyond that, so 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 and resource: stop/delete a repeating invoice, with the added qualifier 'for good' that pins down the delete semantics. It does not name or distinguish itself from the near-identical sibling purchasing_delete_repeating_bill or position itself relative to invoices_save_repeating, so an agent must infer it from the resource name.

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?

Usage context is only implied: 'for good' signals a permanent action, which nudges toward using it only when no further invoices are wanted. There is no explicit when-to-use/when-not guidance, no mention of the alternative (editing via invoices_save_repeating), and no prerequisites such as plan or permission requirements.

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