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

Annotations already disclose the tool is read-only, idempotent, and non-destructive. The description adds a unique data accuracy contract, explaining that only returned fields are verified and derived metrics must be calculated with transparency. This goes beyond the annotations, though it does not cover rate limits or error handling, which is acceptable given 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?

The first sentence is concise and informative, but the description then launches into a lengthy data accuracy contract that includes irrelevant examples such as 'campaign budgets', 'ROAS', and 'CPA', which are unrelated to YouTube video metadata. This bloats the description and weakens its focus, though the structure is otherwise front-loaded with the core purpose.

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?

With no output schema, the description adequately lists what the tool returns and provides a clear rule for handling derived metrics. The extraneous campaign-related terms create some noise, but the overall guidance is sufficient for an agent to use the tool correctly. Not a 5 because of the confusing irrelevant examples that slightly detract from completeness.

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 100%: the single parameter 'video_ids' already has a description in the schema (list of YouTube video IDs or URLs, max 50). The description does not add any further parameter-level detail, so it stays at the baseline for full schema coverage.

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 retrieves detailed information about one or more YouTube videos, enumerating specific fields (title, description, view/like/comment counts, duration, tags, thumbnails). This distinctly separates it from sibling tools like get_youtube_comments or get_youtube_transcript, which serve different purposes.

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 gives clear context for when to use this tool (need detailed YouTube video metadata) and implicitly distinguishes it from siblings that handle comments, transcripts, or analytics. However, it does not explicitly name alternatives or state conditions when not to use it, so it falls just short of a 5.

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