VidLens

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

With no annotations provided, the description carries significant behavioral weight: it discloses processing approach ('intelligent multi-query ranking', 'parallel enrichment'), latency costs ('[~2s quick, ~5-10s standard, ~15-30s deep]'), return structure ('ranked videos with transcript summaries, key moments'), and crucial agent-side obligations ('ALWAYS create visual charts... immediately').

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?

Though lengthy (8+ sentences), the description is well-structured with critical priority instructions front-loaded ('ALWAYS use this tool FIRST'), followed by prohibitions, core functionality, return values, mandatory side effects, and parameter guidance. Every sentence provides actionable guidance for a complex 12-parameter tool.

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?

Excellent completeness given no output schema exists. Describes return values ('ranked videos with transcript summaries'), processing characteristics ('parallel enrichment'), timing implications for agent planning, and mandatory follow-up behaviors (chart creation), covering the gaps left by missing structured output definitions.

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?

With 92% schema coverage, the baseline is high, but the description adds valuable semantic context for enum parameters (explaining 'specific' vs 'explore' modes and the three depth levels with concrete outputs for each) and reinforces the query/searches mutual exclusivity implied in the 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?

The description clearly states the core action ('Searches YouTube directly with intelligent multi-query ranking') and explicitly distinguishes this tool from web search ('Do NOT use web search... use this tool instead') and implies distinction from analysis-focused siblings like analyzeVideoSet by emphasizing it's for discovery/exploration and should be used FIRST.

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 explicit when-to-use ('ALWAYS use this tool FIRST when the user wants to find, discover, or explore YouTube videos'), clear alternative exclusion (web search), and detailed parameter guidance ('Use specific mode to find one best video', 'Use explore for topic discovery') including timing expectations for depth settings.

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