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

Annotations already declare readOnlyHint=false, openWorldHint=true, destructiveHint=false, but the description adds real value beyond them: it validates that unbalanced lines are refused, states it changes the ledger, returns the entry with its lines, requires per-call confirmation (switchable off), and names the credential dependency. It discloses a lot for a mutation tool, though the phrasing on confirmation is muddled.

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 front-loads the core action but then sprawls across package requirements, confirmation behavior, credential needs, and an awkwardly worded privacy note ('Reaches other people'). Several sentences are useful, but the flow is disorganized and some content is redundant with the API key/preconditions theme.

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 write tool with no output schema, the description covers safety-relevant behavior (validation, ledger mutation, confirmation), auth (Cotlet API key, inKaart package), and return information (returns the entry with its lines). Little 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 coverage is 100%, so all three parameters are fully documented in the schema itself. The description restates the debit/credit balance requirement for lines but adds no syntax or format detail beyond what the schema already provides, so the baseline of 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?

The description names a specific verb (Books) and resource (memorial entry / memoriaalboeking) and clarifies it carries debit and credit lines, which distinguishes it from sibling invoice/payment tools like snelstart_create_sales_invoice or snelstart_register_payment. It is clear, but it never explicitly contrasts with those siblings, so it stops short of 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 prerequisites (needs the inKaart package, needs the user's Cotlet API key) and a behavioral rule (refuses unbalanced lines), plus a confirmation default. However, it never states when to choose this over the other SnelStart entry tools, leaving usage context implied rather than explicit.

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