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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world behavior. The description adds meaningful state-machine details: 'reading', 'ready', 'failed', and 'purchased', including the follow-up action for 'purchased.' It does not mention auth or polling limits, but it adds substantial behavioral context beyond annotations.

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?

The description is a single compact sentence with the action front-loaded and the return states clearly enumerated. There is no wasted text.

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 simple polling tool with no output schema, the description supplies the key return states and the follow-up action for the 'purchased' case. The main gap is claim_token semantics, but the overall usage context is otherwise sufficient given the annotations.

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?

There is one required parameter, claim_token, and schema description coverage is 0%, so the schema provides no semantic help. The description never explains what claim_token is, where it comes from, or its format; 'started by get_video_sample' only loosely implies the source.

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: 'Poll a sample started by get_video_sample.' It also enumerates the possible return states, which makes it clearly distinguishable from get_video_sample (start) and sign_in (purchased path).

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 states the precondition that the sample was started by get_video_sample, and it names sign_in as the alternative when state is 'purchased.' It does not specify polling cadence or stop conditions, but the when-to-use context is clear.

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