Search within a channel

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

The readOnlyHint and openWorldHint annotations already signal safe read-only behavior. The description additionally discloses that results are relevance-ranked rather than keyword-matched, including the non-obvious fact that matching videos may lack the query in their title; this is meaningful behavioral context beyond the schema.

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 two sentences are front-loaded and free of waste. The first sentence defines the operation and scope, and the second guards against an agent misinterpreting relevant results that do not contain the query text.

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?

Given the rich input schema, existing output schema, and read-only annotations, this is nearly complete for an agent insert-correct call. The small gap is that it does not state what happens when no channel is identified or how to route among the similar channel/playlist siblings, which agents must infer from sibling names.

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 materially deepen any parameter beyond what the schema already documents, such as q, the channel identifier forms, or pagination token.

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 action and scope: search videos inside one channel. It also adds the YouTube-native relevance-search detail, which clearly separates it from a general YouTube search or a plain channel listing sibling.

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?

There is clear context: this is for searching within a single channel using YouTube's relevance ranking, so an agent can distinguish it from cross-YouTube search or listing tools. It does not explicitly name when-not-to-use alternatives or provide exclusions, so it stops short of a 5.

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