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

The description adds meaningful behavioral context beyond the annotations: 'Listings are cached for a few hours; a fresh enumeration counts against the same daily allowance as uncached fetches.' This introduces caching and quota-cost trade-offs that the agent would not otherwise know from readOnlyHint, openWorldHint, or idempotentHint alone. It does not contradict any annotation.

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: the first states the core function and output, the second gives usage guidance and behavioral caveats. There is no filler, every sentence earns its place, and the most important information is front-loaded.

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 two-parameter read-only tool with an output schema and annotations covering safety and open-world semantics, the description covers the essential context: what it lists, how to use it with a sibling, and the caching/rate-limit caveat. Nothing needed 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 baseline is 3. The description does not add meaning to the url or limit parameters beyond what the schema already provides; it focuses instead on output content and workflow. This is acceptable because the schema already documents both parameters fully, but the description contributes no additional parameter-level insight.

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 precise resource ('the videos of a YouTube channel or playlist'), and the exact fields returned ('date, video ID, and title'). It also distinguishes itself from the get_transcript sibling by explicitly routing to it as a next step, so an agent can tell immediately what this tool does and what it does not do.

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 usage context: 'Use this to answer questions about a channel — pick the relevant videos by title, then call get_transcript for each one.' This clearly tells an agent when to use the tool and how it fits into a larger workflow, directly naming the sibling tool that should follow. It implicitly excludes get_transcript as a substitute for listing.

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