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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the read-only safety profile is fully covered. The description adds only that the lookup is by a single ID; it says nothing about permissions, behavior on missing/invalid IDs, or what is returned, so it barely exceeds the annotation baseline.

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?

Two short, front-loaded sentences with no filler. They are, however, near-synonymous ('Retrieve a video' / 'Fetch a single video post by ID'), so one sentence would have carried the same information.

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-ID getter with no output schema and full annotation coverage, the definition is minimally viable. It omits failure behavior and any hint of the returned video shape, which an agent calling this in a pipeline would benefit from knowing.

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 with 0% schema description coverage, so the schema documents nothing beyond type and a pattern. The phrase 'by ID' confirms the videoId is a lookup key, which adds minor meaning, but no format, example, or accepted-ID guidance is provided to compensate for the coverage gap.

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 ('Retrieve a video', 'Fetch a single video post by ID'), and 'single ... by ID' implicitly separates it from listVideos and getVideoStatus. However, it never names or routes against those sibling getters, so the differentiation is left to inference.

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?

No when-to-use guidance and no exclusions. With siblings like getVideoStatus, getPost, and listVideos present, the definition should say when this retrieval is appropriate versus a status check or a list call, but it offers nothing.

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