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

Annotations already declare readOnlyHint=false and openWorldHint=true, but the description adds meaningful operational context: it mutates the ledger, confirmations apply by default and can be disabled, and it requires the user's Cotlet API key with access to the app. This goes beyond the structured safety hints.

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 purpose is front-loaded and the entry-field summary is efficient. There is mild redundancy between 'By default you confirm each call' and 'confirm with the user before each call,' but no significant 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?

For a book-changing mutation with no output schema and full schema coverage, the description covers what an agent needs: mutability, confirmation workflow, and credential requirements. Success/return behavior is the only minor gap.

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%, so the schema already documents all eight parameters, establishing a baseline of 3. The description restates the key fields and notes VAT is optional, but adds no syntax or constraints not already present in the schema (the negative-amount semantics are duplicated from the amount property).

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 ('Post a finance voucher to a journal') and enumerates the entry fields, distinguishing it clearly from siblings like e-conomic_book_invoice and e-conomic_list_journal_entries. An agent can identify the operation without opening the 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?

It warns 'it changes the books, so check the accounts in the call' and explains the default per-call confirmation, which is useful pre-call context. However it does not state when to use this voucher tool versus sibling posting tools such as e-conomic_book_invoice, leaving the selection decision implicit.

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