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

With no annotations, the description carries the full burden. It usefully discloses the sort order (by video count descending) and what each row contains (video counts, categories), which goes beyond the schema. It does not confirm the read-only, non-destructive nature of the call or any pagination/truncation behavior beyond the limit cap already in 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?

Two sentences, purpose first, usage second, with no filler. The only mild redundancy is the restatement of "BuildFeed covers" versus "tracked by BuildFeed" in the usage sentence.

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 read-only list tool with two fully documented optional parameters and no output schema, the description covers purpose, use case, filtering, and return shape plus ordering. An agent has enough to call it correctly; only the absence of explicit read-only framing and sibling routing keeps it from a 5.

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 schema already explains both limit and category, including defaults and the hard cap. The description only restates the category filter at a high level ("optionally filtered to a category") and adds no syntax or semantics beyond the schema. Baseline 3 applies.

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?

States a specific verb and resource ("List YouTube channels tracked by BuildFeed") and adds scope details: video counts, categories, and sorting order. It does not explicitly differentiate itself from siblings like list_categories or list_videos, but the resource noun is unambiguous enough for selection.

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?

"Use this to discover which creators BuildFeed covers" gives a concrete use case, and the optional category filter narrows the condition. There is no statement of when NOT to use it or which sibling to prefer for adjacent needs (e.g., listing videos vs. channels).

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