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

Goes well beyond the annotations (readOnly=false, destructive=false, openWorld=true) by disclosing that the call 'changes the books', that confirmation is on by default and can be switched off, that it 'reaches other people' requiring user confirmation, and that it needs a Cotlet API key with app access. This is exactly the auth/confirmation context the annotations do not carry.

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?

Front-loaded with purpose and scope, but the confirmation point is made twice ('By default you confirm each call' and 'confirm with the user before each call'), which is mildly redundant. Still, every other sentence earns its place.

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 book-mutating tool with no output schema, the description covers safety, confirmation workflow, prerequisites (API key), and the alternate path. Nothing an agent needs to call it correctly is missing.

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%, so the schema already documents date, amount, journal, and invoice_id. The description reinforces the journal concept ('bank or cash journal that is not linked to a bank account number') but adds no syntax or format detail beyond the schema, 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 ('Registers a purchase or sales invoice as paid in a bank or cash journal') and scopes it to a narrow scenario. An agent can distinguish this from invoice-creation or bank-linking siblings without opening a schema.

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?

Explicitly gives the when-to-use condition ('only for administrations without a bank connection or manual bank statement import') and the when-not alternative ('otherwise the payment must be linked to the bank transaction instead'). Also names the equivalent manual action (Betaling registreren) for grounding.

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