get_channel_info

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

With no annotations, the description carries the full burden. It discloses the API key requirement and the type of data returned, but omits details about error behavior, rate limits, or explicit read-only semantics. The word 'Fetches' implies non-mutating, which adds some clarity.

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 wasted words. It front-loads the primary purpose, then addresses input flexibility and the API key requirement, all in a clear, compact structure.

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 simple one-parameter fetch tool without an output schema, the description covers purpose, input formats, a prerequisite, and sample return fields. It is complete enough for basic usage, though it could mention error scenarios or sibling tool distinctions.

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 already provides 100% coverage with a detailed description of the single parameter, including the UC prefix and auto-extraction from video URLs. The description mostly repeats this information without adding extra semantic meaning beyond the schema.

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 clearly states the tool fetches YouTube channel details and lists specific fields like name, subscriber count, and total views. This specific verb+resource framing distinguishes it from sibling tools like get_video_info or get_transcript.

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 provides context on accepted inputs (channel ID or video URL) and the API key requirement, but it does not explicitly compare this tool to alternatives or state when not to use it. Usage is implied rather than directly guided.

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