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

Annotations already declare readOnlyHint=true, so 'Read-only' in the description is largely redundant, though it reinforces the safety profile. The added GET endpoint is minor context but the description says nothing about pagination behavior, result ordering, or scope limits, which is the kind of detail that would earn credit beyond the annotations.

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?

Three short fragments, front-loaded with the core action and free of filler. The 'Read-only' clause repeats the annotation and the endpoint fragment is marginal, slightly reducing signal density.

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 simple read-only list tool, annotations cover safety and the schema covers all inputs, so the description needn't explain the response. It lacks only notes on pagination semantics (already partly in schema) and any scope constraints, leaving it nearly complete.

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%, with all three parameters (videoId, pageSize, currentPage) documented including defaults and max values. The description adds no parameter meaning beyond the schema, 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 ('List chapter tracks for a video'), which is unambiguous and distinguishable from siblings like apivideo_list_captions or apivideo_list_videos by the 'chapters' resource. It stops short of explicitly naming when to prefer it over related list tools, so it's clear but not sibling-differentiating at the highest level.

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 no when-to-use context, no prerequisites (e.g., that the video must exist or be owned), and no comparison to alternatives. 'Read-only' hints at the safe-read context but is not usage guidance.

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