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

The description discloses important behavior not present in the annotations: the tool returns a URL rather than performing the upload itself, the URL is secret and short-lived, and there is a 5 GB limit. This adds meaningful context beyond the generic annotation hints.

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?

The description is a single sentence with no filler. It front-loads the core action ('Return a secret, short-lived PUT URL') and states the size limit efficiently.

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 simple three-parameter tool with an output schema and clear annotations, the description provides enough context for correct invocation. It covers the essential behavioral details; only explicit sibling routing or failure scenarios are absent, and those are not critical here.

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?

The input schema already provides 100% coverage with descriptions for bucket_name, object_key, and bucket_token, so the baseline is 3. The description adds the size limit but no parameter-specific syntax, which is acceptable given the schema's completeness.

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?

The description uses a specific verb ('Return'), names the exact resource ('a secret, short-lived PUT URL'), and states the size cap ('up to 5 GB'). This clearly distinguishes the tool from siblings like download_object and clarifies that it does not upload content directly.

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?

The usage is implied: the tool provides a PUT URL for uploading an object. However, it does not explicitly mention when to choose this tool over alternatives or any exclusions, leaving some routing decisions to inference.

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