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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is fully covered. The description adds context about what is measured and the grouping dimension, but says nothing about aggregation caveats, freshness, or limits. With annotations carrying the safety burden, this is adequate but thin.

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?

Front-loads what the tool returns, then follows with the parameter note in a compact two-sentence block. Efficient with no filler, though the uppercase emphasis on 'FIND' is stylistic rather than informative.

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?

An output schema exists, so return fields need not be described, and annotations cover the safety profile. For a simple two-parameter analytics tool, the description is complete enough to invoke correctly; only minor caveats about aggregation or date-window behavior are absent.

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 0%, so the description must carry the load and it largely does: 'channel = from youtube_channels' gives provenance plus the empty-string condition, and 'last N days' maps to the days window. It does not restate the 28-day default, but the semantic meaning of both parameters is clarified beyond the bare 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?

States a specific verb+resource: it reports views and watch time broken down by traffic source type, with the metric set and grouping dimension named explicitly. This is enough to distinguish it in practice from youtube_overview and youtube_top_videos, though no sibling is named. Clear and specific, but not explicitly differentiated from siblings.

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?

Provides a useful conditional for the channel parameter ('leave empty if there's only one channel') and implies the days window ('last N days'). However, it never says when to choose this tool over youtube_overview, youtube_top_videos, or youtube_channels. Usage is implied rather than stated.

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