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

Goes well past the annotations (which only say non-readonly, non-idempotent, non-destructive) by disclosing that the URL is a bearer-style secret completing the submission under the caller's identity, that no key is needed on the POST, and that the HTTP response is the trust report. It also adds lifecycle semantics the annotations cannot express: 2-hour expiry and supersede-on-one-shot behavior.

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 sentences, all substantive, with the core outcome (reserves + returns upload_url) front-loaded before the identity caveat and the alternative path. Slightly dense — the identity warning and the expiry note each carry a lot of compressed meaning — but nothing is 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?

For a tool with no output schema, the description still explains what comes back (upload_url from the call, trust report from the POST) and how the submission terminates. The identity, key, and expiration semantics cover everything an agent needs to invoke it without breaking the flow.

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 80%, so place_id, url, agent and expected_reviews are already documented in the schema and the description mostly restates the payload/agent-identity idea. It does introduce submission_id, which is not an input parameter here, so it adds routing context rather than parameter meaning; baseline 3 fits.

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?

Opens with a specific verb and resource — 'Reserves a submission and returns an upload_url' — so the agent knows both the side effect and the return value immediately. It is clearly separable from siblings: submit_reviews is named as the chunked alternative and finalize_submission is implicitly the other end of the lifecycle.

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 routing conditions: use this when you can POST the full JSON payload from your own environment or the user's browser, and use submit_reviews instead when feeding submission_id in inline chunks. It also points to describe_review_source for payload format, leaving no ambiguity about which tool to reach for.

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