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 valuable behavioral context: it is a heuristic proxy, not a simulation of YouTube's review process, and it returns a risk band, numeric score, and the single most severe flag. It also discloses that the full flag-by-flag report is a separate paid product, which is important for setting expectations. No contradiction with annotations.

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 criteria, then the output summary, then the heuristic caveat and paid-product disclosure. Every sentence earns its place, though the paid-product sentence is slightly promotional and could be trimmed. Still, it is efficient and well-structured.

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 single-parameter read-only tool with no output schema, the description is complete enough: it states inputs, criteria, output shape, and the heuristic nature. It does not specify the exact numeric score range or how many uploads are checked, but those are minor gaps given the tool's simplicity and the annotations covering safety. A 4 is appropriate.

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 documents the single parameter ('channel') with examples. The description does not add much beyond the schema, but it does imply the channel is a YouTube channel handle/URL/ID, which aligns with the schema. Baseline 3 is appropriate because the schema carries the parameter documentation 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 states a specific verb ('Check'), a specific resource ('a YouTube channel's recent uploads'), and the specific policy criteria (title/description repetition, upload-cadence regularity, AI-disclosure language). It also clearly distinguishes this from siblings by naming the exact policy and output (risk band, numeric score, most severe flag).

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 clearly implies when to use this tool: when an agent needs to assess a YouTube channel's risk under YouTube's 2026 inauthentic-content policy. It does not explicitly name alternatives or exclusions, but the context signals show many sibling tools with different purposes, and this description is specific enough that an agent can route correctly. It lacks an explicit 'use this instead of X' statement, so not a 5.

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