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

With no annotations, the description carries the full burden and does well: it discloses the 15-minute URL expiry, that confirm_upload is what actually creates the file record and block, the supported MIME types, and that the returned mime_type must be used in the PUT header. It stops short of stating permission requirements or file size limits, so a small gap remains for a multi-step mutation.

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?

Purpose is front-loaded in the first sentence, followed by a numbered flow that mirrors the actual call sequence. The expiry note and supported-types list are compact and each sentence carries operational information; nothing is redundant.

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?

Although there is no output schema, the description names the returned fields (upload_url, file_id, s3_key) and describes the downstream shell command and follow-up call, so the agent knows both what comes back and what to do with it. Complete for a three-parameter, multi-step tool.

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 baseline is 3, but the description adds real value beyond the schema: it names the exact call signature get_upload_url(page_id, filename, mime_type), enumerates the supported file type families, and explains that mime_type drives the PUT Content-Type header. This is meaning the schema alone does not convey.

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 gives a specific verb and resource ('Get a presigned URL for direct file upload') and immediately distinguishes the approach from its alternative ('avoids sending file data through MCP, saving tokens'). An agent can separate this from get_image_url, get_file_text, or confirm_upload without opening any 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?

It lays out an explicit three-step workflow with the exact arguments for each call, names the sibling tool confirm_upload that must follow, and states the trade-off (token savings) that motivates choosing this path over in-band upload. There is no inference required about when to use it.

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