get_youtube_performance_history

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

With no annotations, the description must disclose all behavioral traits. It states the cost (3 credits) and that it returns an array of timestamped snapshots. However, it does not mention side effects (none expected), rate limits, or authorization requirements, leaving gaps for a tool that credits cost.

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 three concise sentences, front-loaded with purpose, and includes essential details (metrics returned, array structure, cost). No redundant information.

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?

No output schema is provided, so the description should fully explain the return format. It mentions the 'histories' array but does not detail the structure of each snapshot (e.g., field names, types). Metrics are listed but not mapped to fields, leaving ambiguity.

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?

Both parameters are fully described in the schema (100% coverage). The description adds no new parameter meaning beyond the schema's detailed notes (e.g., channelId format restrictions). Baseline of 3 is appropriate.

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 daily metric snapshots for a YouTube creator, specifying subscribers, total content count, and all-time performance. It distinguishes from sibling tools like get_youtube_performance (likely current data) and get_youtube_audience (audience-specific) by focusing on historical time series.

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 implies usage for historical performance data over N days but lacks explicit guidance on when to use over alternatives. No mention of prerequisites (e.g., valid channelId) or when not to use (e.g., if only current data needed).

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