Get Keyword Roots for a Niche

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

With readOnlyHint=true annotation already covering the safety profile, the description adds valuable behavioral context by detailing the output structure ('roots' and 'normalizedRoots' tables) and the meaning of each field (frequency, broadSearchVolume, broadSearchVolumeRatio). It also explains the extraction logic via an example, going beyond what annotations provide. No contradiction with annotations.

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 well-structured: first the usage triggers, then the operation, then the detailed output fields. The example is illustrative and every sentence provides necessary information without redundancy. It is appropriately sized for the tool's complexity.

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?

Since there is no output schema, the description takes responsibility for explaining return values. It thoroughly describes the tables (roots, normalizedRoots), each field (root, frequency, broadSearchVolume, broadSearchVolumeRatio), and additional metadata (per-keyword breakdowns, latestResearchDate). It also covers usage context, making it self-sufficient for an agent to select and invoke the tool correctly.

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?

The schema already fully documents the only parameter nicheId (including the note 'from list_niches'), giving 100% schema coverage. The tool description does not add further semantic detail about the parameter itself, so the baseline score of 3 applies despite the description's broader context.

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 the keyword lexical roots for the Niche' and provides a specific example ('bluetooth headphones' yields 'bluetooth', 'headphones', 'bluetooth headphones'). It distinguishes itself from sibling tools like get_niche_keywords by focusing on derived roots rather than raw keywords, and ties to user intent ('highest-impact words', 'prioritize terms').

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 opens with explicit 'Use this when...' and lists three concrete triggers: 'find the highest-impact words across a niche's keywords', 'asks about keyword roots', and 'wants to prioritize terms for a listing'. However, it does not specify when not to use the tool or mention alternative tools (e.g., get_niche_keywords), so it lacks the 'when-not' or alternatives detail needed for a 5.

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