create_upload_url

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

Beyond annotations, the description discloses important behavior: the upload URL is valid for about ten minutes, the PUT must match Content-Type and Content-Length exactly, and already_exists allows skipping the PUT. It also names the required follow-up tool and returned id. With annotations already covering safety and openness, this adds substantial operational context.

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 front-loaded with purpose, then gives a compact procedural sequence and an edge-case rule. Every sentence carries operational value with no redundant restatement of structured fields. It is appropriately sized for the workflow.

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?

Given eight parameters, an output schema, and annotations, the description covers the essential workflow: create URL, PUT bytes, handle already_exists, then confirm. The output schema removes the need to explain return values. A minor gap is not naming the upload_file sibling as the alternative path.

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 parameter documentation is already strong. The description reinforces that content_type and size_bytes must be used exactly as Content-Type and Content-Length during the PUT, but it does not add meaning for the other six parameters beyond what the schema provides. Baseline 3 is appropriate.

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 states a specific verb and resource: 'Starts a direct-to-storage upload'. It also scopes the use case to 'bytes this server can't read', which helps distinguish it from server-read upload paths. However, it does not explicitly name or differentiate from the sibling upload_file tool, so it falls short of full sibling clarity.

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?

It gives clear when-to-use context ('bytes this server can't read') and a concrete follow-up procedure: PUT with exact headers, then call confirm_upload. It also handles the already_exists shortcut. It does not explicitly state when to use upload_file instead, so alternatives are implied rather than named.

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