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

Annotations only declare the safety profile (readOnly=false, destructive=false, idempotent=false). The description adds substantive behavior the agent cannot get elsewhere: a 10 MiB size cap, the required HTTP PUT method and content type, a 2-hour URL expiry, and the chaining into extract_brand_kit. This is exactly the value-add expected when annotations already cover safety.

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 sentences, each carrying distinct load-bearing information (what it makes, how to use the URL, how long it lasts) with the core purpose front-loaded. No filler.

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?

With no output schema and no nested objects, the description still supplies the return artifact (assetPath), the size/size-limit and expiry constraints, and the downstream step. An agent has everything needed to invoke it correctly and act on the result.

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?

There is a single brandId parameter with 0% schema description coverage, and the description never explains it, nor does it note that brandId is not required (requiredParameters=0). The intent is inferable from context but not stated. This is the weakest dimension.

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: 'Create a private signed upload URL for a brand manual PDF.' This cleanly separates it from the sibling upload_brand_logo (logo image vs. manual PDF) and get/update_brand_kit (retrieval vs. URL provisioning). An agent can identify the operation without opening the 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?

Gives an explicit end-to-end workflow: PUT the PDF bytes with Content-Type application/pdf, then pass assetPath to extract_brand_kit. That names the follow-up tool and the condition for using it. It stops short of stating when NOT to use it (e.g., vs. upload_brand_logo), so it is clear context without exclusions.

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