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

Adds operational context beyond the annotations: cover validation is independent of readiness, and a lost response should not be treated as failure — consistent with idempotentHint=true. What remains undisclosed is what the response contains ('Poll ready' is never specified) and what happens if the PUTs were not actually completed.

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 short sentences with no filler, and the precondition is front-loaded. The telegraphic style ('Poll ready', 'MPS') costs some readability but nothing is wasted.

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?

With no output schema, the description should say what the completion response looks like or what 'ready' refers to, and it does not. It also leaves acronyms like MPS unexplained, though the critical sequencing and retry guidance is present.

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 single required parameter session_id has 0% schema description coverage, and the description never mentions it or clarifies that it identifies the upload session being completed. The agent must infer the parameter's meaning from the tool name alone.

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 action ('request completion') and the precondition ('after thumbnail and video PUTs are acknowledged'), which distinguishes it from siblings such as cancel_upload or resume_upload. However, it never names the resource being completed (the upload session) explicitly, so an agent must infer that from the schema's session_id.

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 real timing guidance: call only after both PUT types are acknowledged, poll for readiness, and do not block on MPS check_status. It stops short of naming alternatives (e.g. that resume_upload handles incomplete parts) but the when/when-not conditions are clear.

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