hetzner_get_latest_invoice

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

Annotations already declare readOnlyHint true and destructiveHint false. The description adds value by explaining the inner mechanism (fetches first page of invoices) and credential requirements. No contradictions with annotations.

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?

The description is concise with no wasted words. It front-loads the core action and adds necessary context in a structured manner. Every sentence adds value.

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?

The description fully covers the tool's purpose, method, requirements, and a suggested use case. With an output schema present, the lack of return value details is acceptable. For a simple tool, it is complete.

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 0% (no description for the 'ctx' parameter). The description does not mention or explain the parameter at all. For a low-coverage schema, the description should compensate, but it fails to do so.

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?

The description clearly states 'Get the most recent Hetzner Cloud invoice' and explains it fetches the first page and returns the latest one. It distinguishes from siblings like 'hetzner_list_invoices' and 'hetzner_get_invoice' by focusing on the latest invoice.

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?

The description provides good context: it requires HETZNER_ACCOUNT_EMAIL and HETZNER_ACCOUNT_PASSWORD, and suggests using it for automated monthly bookkeeping followed by 'oc_create_expense'. However, it does not explicitly state when not to use this tool or compare it to alternatives.

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