search_channel_videos

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

No annotations are provided, so the description carries the transparency burden. It discloses the cost: 'Costs 100 YouTube quota units per 50 results,' which is a behavioral trait not visible in the schema. However, it does not mention return format, error handling, or read-only nature beyond the implication of 'search,' so it is not a 5.

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, front-loaded with the core purpose, and each sentence earns its place: one for what it does, one for cost and alternative. No fluff or repetition of schema-contained information.

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 tool's complexity (6 params, output schema present, no annotations), the description covers purpose, cost, and an alternative, and the schema handles parameter semantics. It lacks only minor operational context such as error conditions, but the combination of schema and description is sufficient for selection and invocation.

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?

The input schema provides 100% coverage with descriptions for all 6 parameters, so the baseline is 3. The description adds only a usage example, not extra parameter-level detail, so it neither improves nor harms parameter understanding.

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 opens with 'Search one channel's videos by keyword,' which is a specific verb+resource+scope statement. It distinguishes from the sibling tool list_channel_videos by explicitly noting the alternative for keywordless recent uploads, making the purpose unambiguous.

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 explicitly states when NOT to use this tool: 'When you want recent uploads and have no keyword, use list_channel_videos instead — it is 100x cheaper.' It gives a concrete use-case example (latest iPhone review on MKBHD) and compares cost to the alternative.

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