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

Beyond the annotations (which only say non-read-only, non-idempotent, non-destructive), the description adds real behavioral facts: links expire after 1 hour and a verification value is returned alongside them. It does not explain why the call isn't idempotent (e.g. repeated calls mint new links) or whether payment gating produces an error an agent could handle.

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?

It is a single dense paragraph that front-loads what the file is before moving to availability, return values and per-format requirements. Some clauses ('once it is ready and paid (or covered by the API key's plan)') are run-on, but nothing is padding.

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 8 params, a nested object and no output schema, the description covers the essentials: gating condition, returned links and their expiry, the verification value, and conditional per-format inputs. The remaining gap is that 'the verification' is never defined, and error behavior when the job is unpaid is unmentioned.

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 100% and the schema already documents each parameter with patterns, enums, defaults and conditionality, so the description's format-specific notes (datev.berater_nummer / mandanten_nummer for anonymous jobs, account_iban for MT940) largely restate what is already there. A baseline 3 is appropriate, with no meaningful extra meaning added.

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 names a specific action (download the final, verified file) and enumerates the concrete output artifacts (DATEV Buchungsstapel, Lexware CSV, MT940), so an agent knows exactly what it produces. It does not explicitly distinguish itself from the closest sibling, get_preview, which is the main thing keeping it from a 5.

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?

It gives a clear precondition for use: the file must be ready and paid (or covered by the API key's plan). That context tells an agent when to call it, but it never says to poll get_job_status first or that get_preview exists for an early look, so alternatives and exclusions are left implicit.

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