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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered by structured data. The description adds genuinely useful non-annotation context: the permission scoping ('allowed to view'), the full status lifecycle, and the fact that 'failed' carries a separate failure field. It doesn't mention errors, not-found handling, or polling cadence, which keeps it from a 5.

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?

Front-loaded with the core action and usage directive in the first sentence, then the status reference. The status enumeration is long but each term earns its place since there is no output schema documenting them; still, it reads as a dense run-on that could be structured as a list.

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 single-resource read with no output schema, the description supplies exactly the missing return semantics: the ordered status lifecycle and the final-state set. Combined with the permission scoping note, an agent has enough to poll and interpret results correctly.

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?

Only one parameter and schema description coverage is 100%, so the schema already documents submission_id fully – baseline is 3-4. The description adds only that the ID can refer to a submission 'on any platform,' marginal but useful disambiguation over the schema.

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 verb ('Fetch') and resource ('a single video submission') with explicit scope ('the authenticated user is allowed to view') and platform coverage. The word 'single' cleanly distinguishes it from the sibling list-submissions-tool without the agent needing to open either 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?

Explicitly says 'Use it to poll a submission until status is final,' which tells the agent the intended usage pattern. It does not name an alternative tool or state when not to use it (e.g., vs list-submissions-tool for bulk reads), so it stops short of full routing guidance.

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