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

Annotations declare readOnlyHint=true and openWorldHint=true, so the agent already knows this is a safe read operation with open-world grounding. The description adds the grounding basis ('what already converts on their own YouTube channel and what their audience asks for') and the output nature ('light title/thumbnail direction'), which is useful behavioral context. However, it doesn't detail rate limits or the format/depth of the returned evaluation. A 3 is appropriate given annotations already carry the safety profile.

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?

Three sentences, front-loaded with purpose, then usage, then the alternative. Efficient with no wasted words, though slightly dense. The routing to package_video is well-placed at the end.

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 read-only evaluation tool with annotations covering safety and no output schema, the description provides the grounding basis and output nature ('light title/thumbnail direction'). It routes to the sibling for deeper needs. The main gap is unclear parameter semantics due to low schema coverage, but the description is otherwise complete for an agent to call it correctly.

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 coverage is only 33% – only 'idea' is described in the schema, while 'title' and 'topic' are undocumented. The description mentions 'idea, topic, or title' but doesn't clarify how they relate (e.g., whether topic and title are alternatives to idea or supplementary). With low coverage, the description should compensate but only partially does so.

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 (judge/evaluate) and resource (a YouTube video idea, topic, or title) and grounds it in concrete data sources (own channel's conversions, audience asks). It also names the sibling it is not (package_video) for deeper packaging, making it distinguishable from other siblings like suggest_ideas.

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?

Explicitly states when to call it ('whenever the user proposes an idea and asks whether it (or a title) is worth making, will work, or is a good idea') and when to use the alternative ('For deeper packaging help... use package_video instead'). This is a clean when/when-not/alternative structure.

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