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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is partly covered. The description adds workflow context and notes the answer lists other matching payments, but it never explains what the destructive flag destroys, e.g. whether an existing Beleg attachment is displaced by the contract, nor any permission requirements. With annotations present that is a modest but real gap.

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 short lines, front-loaded with the core action and followed by the mandatory next step; nothing is padded. The final sentence about the returned list of other fitting payments is slightly redundant given an output schema exists, a small deduction from ideal.

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 three-parameter mutation with full schema coverage, existing annotations, and an output schema, the description supplies the essential action plus the required follow-up booking step. The remaining gap is the destructive semantics of replacing a Beleg, which matters for an irreversible-feeling mutation but is partially implied by 'in place of a Beleg'.

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 all three parameters are documented in the schema, so the schema does the heavy lifting. The description maps concepts loosely (contract -> dokument_id, payment -> transaction_id) but adds no format, ID-syntax, or validation detail beyond the schema. 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: attaching a stored contract (rent, leasing, insurance) to a payment, and clarifies the substitution relationship to a Beleg. It also names the follow-up tool book_transaction, so the agent knows this is one step in a two-step flow. It does not distinguish itself from near siblings such as attachment_to_beleg or link_beleg, which keeps it below 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?

Gives clear triggering context: use this when a contract, not a Beleg, documents the payment, and immediately states the required next call with the concrete kind="vertrag" argument. No explicit when-not-to-use or exclusion against the Beleg-based siblings is stated, so it falls short of a 5.

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