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

Adds real context beyond the annotations: the customer number is server-assigned, nothing is sent to the contact, and the call consumes API credits with a stated rate and monthly quota. Annotations already cover safety (readOnly=false, destructive=false, idempotent=false), so the credit/quota warning is the valuable extra. It stops short of saying whether the created record is returned or how to retrieve the assigned number.

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?

Four short sentences: operation, side effect, dedupe prerequisite, cost. Front-loaded verb and no wasted clauses — the credit cost is the only arguably optional detail and it is genuinely decision-relevant for a quota-limited API.

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 14-parameter creation tool with no output schema, the definition covers the mutation semantics, dedupe workflow, and cost budget. The remaining gap is what comes back (does the response include the assigned customer number?) — minor since the schema is fully documented.

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 every one of the 14 parameters is documented inline including both enums. The description adds no parameter-level detail, but the schema already does the heavy lifting, 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?

Opens with 'WRITE: create a contact (company)' — an explicit verb plus precisely-scoped resource that separates it from papierkram_create_person and papierkram_create_invoice. The 'WRITE:' prefix also frames the operation type immediately.

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 an explicit prerequisite ('Check papierkram_list_companies first to avoid duplicates') and names the sibling tool to use for that check. It also implies the read-side counterpart for verification, leaving little to inference.

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