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

The description adds behavior beyond the annotations: automatic WebP compression at a 1024px cap and persistence of the resulting URL on the customer record. This is meaningful processing detail. It does not explicitly say the previous logo is replaced, which is the key implication of destructiveHint=true, but the pipeline disclosure is genuinely useful.

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?

Two tight sentences with the action first and the server-side consequence second; nothing is wasted. It is arguably too short given the 0%-documented parameters, but as structure it is clean and front-loaded.

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 destructive mutation with no output schema, the description explains what happens to the image but not the input contract (base64 format, file_name purpose, size limits) or what is returned. Annotations cover the safety profile, so the gap is mainly on parameters rather than behavior.

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 0% across three parameters, so the description carries the full burden — yet it names none of them. It implicitly tells the agent an image is supplied (compressed by the server) and that a customer is targeted, but file_name, the base64 encoding requirement, and size limits on input are undocumented.

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?

Specific verb and resource ('Upload a customer logo') with a clear statement of the server-side outcome. It doesn't explicitly differentiate itself from siblings like upload_item_image or upload_label_asset, but the customer-logo scope is unambiguous.

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?

There is no guidance on when to use this versus upload_item_image or upload_label_asset, nor any prerequisites (e.g., whether an existing logo must be removed first or permissions needed). Usage is only implied by the tool name and the 'stores the URL on the customer' clause.

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