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 the one bit of useful behavior beyond that: pagination via a continuation token. It says nothing about result limits, ordering, or error behavior when the channel is not found.

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 sentences, front-loaded with the usage scenario, then scope, then pagination. No wasted clauses, though the example-heavy opening is near the limit of what's needed.

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 3-parameter read tool with no output schema and full annotation coverage, the description covers selection, scope, and pagination adequately. Return shape and result-count behavior are the only unaddressed items, which is a minor gap.

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 all three parameters are already documented, and the description's note about passing `continuation` for the next page restates what the schema says. Baseline 3 applies since the schema carries the parameter burden.

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 names a specific verb+resource (search videos) and a hard scope constraint: 'Searches only inside that channel.' This cleanly distinguishes it from search_youtube and the list_* siblings, which have no within-channel query semantics.

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?

It gives concrete trigger examples ('what has @hubermanlab said about sleep') and states the scoping condition, which implicitly rules out global search. It does not name search_youtube or list_channel_videos as the alternative for the non-scoped case, so routing is inferable but not explicit.

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