get_youtube_performance

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

No annotations are provided, so the description carries full burden. It discloses the credit cost (2 credits) and the data structure. However, it does not mention rate limits, authentication requirements, or potential side effects. For a read-only tool, the cost disclosure is useful, but other behavioral aspects are missing.

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 front-loaded with the main purpose and then details the return structure efficiently. It is comprehensive but not overly verbose, with each sentence providing distinct information. The use of parentheses for the consistency score bands and growth metrics adds clarity without clutter.

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 must explain the return values thoroughly. It covers all major components: four sibling objects, statistics, engagement block, ranking, growth trends, and posting cadence. This is sufficient for an agent to understand the tool's output and differentiate it from other performance-related tools.

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% with a single parameter (channelId) that has a description. The description reinforces the format requirement (UC… form) but does not add new semantic meaning beyond the schema. Baseline 3 is appropriate as schema already documents the parameter.

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's purpose: 'Get a YouTube creator's engagement metrics.' It details the specific return objects (videosPerformanceRecent, shortsPerformanceRecent, etc.) and metrics, distinguishing it from sibling tools like get_youtube_performance_history which likely focuses on historical data. The verb 'Get' and the resource 'engagement metrics' are specific and unambiguous.

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 lacks explicit guidance on when to use this tool versus alternatives. It mentions the credit cost but does not specify prerequisites, exclusion criteria, or compare with sibling tools (e.g., when to use get_youtube_performance_history instead). The usage context is implied but not clearly stated.

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