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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true; the description reinforces this with 'WRITE' and POST /clients. The dedupe warning adds real behavioral value by implying duplicates are not prevented server-side. It stops short of saying what a duplicate or validation failure returns.

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 sentences, mutation intent front-loaded, then prerequisite, then the alternative path. No filler and nothing buried.

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 ten-parameter mutation with no output schema, the description covers purpose, dedupe risk, and the nearest competing workflow. Still missing what comes back (client ID) and whether country/is_reg_vat have defaults that matter on creation.

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 70%, so the schema already carries most parameter meaning. The description names five fields (name, Bulstat, VAT, address, MOL) but adds no format or conditional logic beyond it, and says nothing about code, town, country, delivery_address, or is_reg_vat's coupling to vat_number.

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 ('add a company client') with a WRITE prefix and enumerates the key fields being supplied. It also draws the boundary against sibling tools: company clients here, individuals via invbg_create_invoice.

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 invbg_list_clients first to avoid a duplicate') and an explicit exclusion with the alternative to use instead ('For an individual (EGN) ... use invbg_create_invoice and is_to_person'). The when and the when-not are both spelled out.

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