Varrd

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

Annotations cover read-only safety (readOnlyHint: true) and external API nature (openWorldHint: true); description adds valuable behavioral context including output format specifics ('concise digest', '↳ line'), temporal scope ('today's news'), and business constraints (credit costs, edge prerequisites) not present in structured data.

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?

Four efficient sentences with zero waste: opening states purpose, second details output format with concrete examples, final two state prerequisites and costs. Information is front-loaded and every sentence earns its place, including the specific '↳' formatting detail.

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?

Despite lacking output schema, description adequately covers return value structure (digest format with annotation lines), prerequisites, and costs. With zero parameters and clear annotations, it provides sufficient context for invocation, though explicit error conditions (e.g., behavior when <5 edges exist) could enhance further.

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?

Input schema contains zero parameters, warranting baseline score 4 per evaluation rules. Description appropriately does not invent parameter semantics where none exist, and the empty schema requires no additional clarification.

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?

Description uses specific verb 'Get' with resource 'personalized market news briefing'. Critically distinguishes from siblings like 'research' and 'search' by specifying it operates on the user's 'validated edge library' and connects headlines to 'your specific book', indicating unique personalization not available in generic research tools.

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 clear prerequisites ('Requires at least 5 strong edges') and cost warning ('Costs credits'), helping determine invocation eligibility. However, it lacks explicit comparison to siblings like 'autonomous_research' or 'research' regarding when to choose this personalization versus generic search alternatives.

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