Create file upload

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

Annotations only establish that this is a non-destructive, non-open-world write. The description adds critical operational behavior the annotations cannot: the return shape { fileId, uploadUrl }, the requirement to PUT raw bytes with NO Authorization header to a short-lived pre-signed URL, and the follow-up get_file call to await processing. That is exactly the extra context that makes invocation succeed.

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?

Four dense sentences, front-loaded with the triggering condition and return contract, then the transport instruction and the follow-up call. Every sentence carries unique operational value; 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?

Despite having an output schema, the description fully covers the end-to-end flow (create → PUT bytes → get_file wait → consume fileId), which is what an agent needs to chain this multi-step upload correctly. Nothing material is missing.

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 all three parameters (type, displayName, isTemporary) are already documented including enum values and defaults. The description adds no parameter-level detail, so the baseline of 3 applies.

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 ('Start an upload for a large file, or when file bytes cannot be inlined') and explicitly distinguishes itself from the sibling upload_file ('For small files, prefer upload_file'). An agent can route correctly without opening either 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 explicit when-to-use conditions (large file, or bytes cannot be inlined), an explicit alternative for the opposite case (small files → upload_file), and the required follow-up sequence (PUT bytes, then get_file with wait:true). Nothing is left to inference.

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