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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, destructiveHint false. The description adds value by explaining internal behavior: 'Probes each entity... with ai_visibility_check, ranks by score, surfaces which is most/least recognized.' No contradictions.

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?

Two sentences, front-loaded with action and outcome. Every clause adds value: what, how, use case, return format. Efficient and clear.

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, but description explains return: 'ranked list with score, confidence, signal density per entity.' Covers purpose, usage, behavioral context, return format. Tool with 4 params (1 required) is fully described.

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 description coverage is 100%, so baseline is 3. The description adds semantics not in schema: 'First entry treated as the subject for narrative; rest are competitors.' This provides behavioral context beyond parameter descriptions.

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 does 'Compare AI visibility across multiple entities side-by-side.' It specifies the verb (compare/scan), resource (competitor AI presence), and distinguishes from sibling tools like ai_visibility_check (single entity) and compare_entities (different comparison).

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?

Description provides explicit context: 'Useful for competitive AI-marketing audits: does Claude know about us as well as our competitors?' While it doesn't explicitly state when not to use or name alternatives, the usage scenario is clear and well-scoped.

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