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. The description adds meaningful behavioral context: it returns complete records with animation tracks, keyframes, extrapolation modes, and style, and it warns against pulling the whole project. It doesn't describe pagination or response size limits, but the output schema exists and the read-only nature is clear. A 4 is appropriate because the description adds value beyond annotations without contradicting them.

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 zero waste. The first sentence front-loads the core purpose and return contents; the second gives the workflow guidance. Every clause earns its place, and the structure is easy to scan.

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 read-only inspection tool with a full output schema, 100% parameter coverage, and annotations covering safety, the description is complete. It tells the agent what to pass, where to get it, what to expect back, and how to use it efficiently. Nothing an agent needs to call it correctly is missing.

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 description coverage is 100%, so the schema already documents both parameters. The description adds value by explaining the source of elementIds (from describe_video's tree) and the intended usage pattern (only for layers about to mutate). It also clarifies the element id format implicitly by referencing describe_video. This goes beyond the schema's basic descriptions, so a 4 is warranted.

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 states a specific verb ('inspect'), a resource ('layers'), and the exact scope: per-element drill-in returning complete records including fields, animation tracks, keyframes, extrapolation modes, and style. It explicitly positions itself as 'the open this layer half of the browser,' distinguishing it from describe_video and other sibling tools. An agent can immediately tell what this tool does and what it returns.

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 explicit when-to-use guidance: pass elementIds read from describe_video, and pull detail only for the handful of layers you're about to mutate, not the whole project. It also implies the alternative (describe_video for the overview) and the workflow relationship. This is clear, actionable usage guidance.

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