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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds that it reads a 'saved overview' and optional 'timestamped section summaries', which hints at the content but not additional behavioral details like pagination or error conditions. With annotations covering the core behavior, the description provides marginal extra context.

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 two sentences with no filler. The main action is front-loaded, and the use case is provided succinctly. Every word contributes to understanding the tool's purpose and when to call it.

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?

Given that the tool has an output schema and the annotations cover safety, the description is sufficient for a simple read operation. It states what the tool does and when to use it, and the parameter semantics are fully in the schema. Nothing critical for calling the tool correctly is missing, though it doesn't explicitly mention potential edge cases like missing summaries.

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?

The input schema has 100% parameter description coverage, so the schema fully documents all seven parameters. The description adds a minor semantic by mentioning 'optional timestamped section summaries' which maps to include_segments, but this is not essential beyond the schema. The baseline of 3 applies since the schema does the heavy lifting.

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 clearly states the action ('Read a video's saved overview and optional timestamped section summaries') and the specific resource (video summary). It provides a clear use case ('Use this when asked what a video is about.'), but it does not explicitly name or contrast with sibling tools like vivu_get_search_results or vivu_search_videos, so it lacks explicit sibling differentiation.

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?

The description gives a clear condition for use ('when asked what a video is about'), which effectively guides an agent toward this tool for that scenario. However, it does not mention when not to use it or name alternatives, so it's not as explicit as a fully differentiated usage guide.

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