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

Annotations already declare destructiveHint=true and idempotentHint=true; the description goes beyond them by explaining the retry contract for pending results and the real side effect that changed media invalidates client approval. It also documents a post-condition (thumbnail becomes ready auxiliary media requiring selection in YouTube settings). It stops short of describing the response shape or failure modes, which matters since there is no output schema.

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 tight sentences, front-loaded with the action and its precondition, then consequences and follow-up. The telegraphic phrasing ('Agency upload', 'retry complete, not reserve') is efficient but slightly cryptic on first read.

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 destructive, idempotent mutation with 100% parameter coverage and annotation support, it covers preconditions, retry semantics, side effects on approvals, and a downstream step. Only permission/auth requirements and the shape of the 'pending' result are left unstated.

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% and all three IDs are documented in the schema with the 'never a personal platformId' warning. The description adds nothing about any individual parameter, so the baseline 3 applies.

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 and resource ('Complete a reserved Agency upload') plus the precondition ('after the HTTP PUT'), which separates it from company_reserve_media. The 'Agency' qualifier hints at the boundary with the sibling complete_media, but that distinction is never made explicit.

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 clear trigger conditions (after reserve + HTTP PUT) and an explicit routing rule away from an alternative: 'A pending result means retry complete, not reserve.' It also imposes ordering against downstream tools ('finish uploads before requesting review or scheduling'), though those siblings are described rather than named.

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