list_chapters

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 useful behavioral context beyond annotations: chapters are returned in timecode order and appear as segments on the player scrubber. It does not discuss pagination or return shape, but that is less critical given the tool's simplicity.

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 core action and ordering constraint are front-loaded, and the second sentence adds relevant context about how chapters are presented. Every word earns its place.

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 one-parameter, read-only listing tool with strong annotations, the description is nearly complete. It conveys the resource, the ordering, and the player-visibility context. The only minor gap is the lack of detail about the returned chapter fields, but the absence of an output schema makes a brief note about the response shape a nice-to-have rather than a necessity.

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% for the single parameter, video_id, described simply as 'Video id.' The tool description clarifies that the video's chapters are being listed, but it does not add meaningful parameter-level detail beyond what the schema already provides. 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?

The description states a specific verb ('List'), a resource ('a video's chapters'), and an organizing constraint ('in timecode order'). This clearly distinguishes list_chapters from sibling mutation tools like add_chapter, update_chapter, and delete_chapter.

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 clearly implies read-only retrieval of chapters, and the sibling tools make the contrast with chapter mutations obvious. However, it does not explicitly state when to prefer this over alternatives or mention any conditions, such as 'use this when you need the full ordered chapter list.'

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