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

Significantly exceeds the minimal destructiveHint=true annotation: it warns that Loyverse does not document whether omitted fields survive an update, so the caller should send the full record. That explains the replace-like semantics behind the destructive hint, which annotations alone cannot convey. No auth or rate-limit context, and the endpoint mention (POST /suppliers/) adds little.

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, front-loaded with the operation and its mode switch, then the caveat, then the endpoint. Every sentence carries weight and none is redundant with the schema.

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 13-parameter upsert with full schema coverage and no output schema, the description covers the operation mode and the main behavioral risk. The remaining gap is modest: no mention of what the call returns for the new/updated record or how errors surface.

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 baseline is 3; the description adds the one piece of semantics the schema implies but does not emphasize — that `id` switches the operation from create to update and that a partial update may wipe unspecified fields. It adds real guidance beyond field-level descriptions.

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+resource (create/update a supplier) and immediately disambiguates the dual mode with the mechanism: 'update one by passing its `id`'. An agent can distinguish this from loyverse_list_suppliers and the other upsert_* siblings without opening any 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 tells the agent how to choose between create and update ('Omit to create' is echoed, and 'update one by passing its `id`'), which is the only real decision for this tool. It stops short of naming alternative tools or stating prerequisites/failure conditions, so it is clear context rather than a full when/when-not treatment.

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