Get Signed Upload URL

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

Annotations declare readOnlyHint=true, which aligns with the tool's read-only nature (generating a URL). The description adds workflow context (PUT and upload_media steps) beyond annotations, enhancing transparency about how the tool fits into the upload process.

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 concise sentences with no wasted words. The purpose is stated first, followed by step-by-step instructions, then an alternative. Structure is clear and efficient.

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 the presence of an output schema (context signal) and the description's coverage of the multi-step workflow, the description is complete enough. It explains the tool's role and next steps, though it doesn't detail the output format (handled by output schema).

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 coverage is 100%, so the schema already documents all three parameters (isVideo, filename, mimeType). The description does not add additional semantic information about the parameters.

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 clearly states the tool obtains a pre-signed S3 URL for direct file upload, using specific verbs ('Get') and resource ('pre-signed S3 URL'). It distinguishes itself from sibling tools like upload_local_file and upload_media by explaining the workflow.

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 description explicitly tells when to use this tool (when you need a URL for direct upload) and what to do after (PUT file, then call upload_media). It also provides an alternative: use upload_local_file for a simpler workflow.

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