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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds the cost ($0.08) and the specific timeline detail ('life_in_days + day_number timelines'), enhancing the agent's understanding of what the tool returns. This goes beyond annotations without contradicting them.

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 short sentences with no filler. The primary capability ('side-by-side notable packs') is front-loaded, followed by the efficiency benefit and a concrete example. Cost is included as a bonus. Every sentence earns its place.

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?

Given the tool's simplicity, a read-only annotation, and the presence of an output schema, the description covers the essential usage: what it does, when to use it over alternatives, and cost. It does not describe return format or edge cases, but the output schema covers that. Slightly incomplete for parameter semantics, but overall sufficient for correct invocation.

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 60% (date, slug_a, slug_b have descriptions; peers and similar do not). The description mentions 'two slugs' and gives an example, but it does not explain the numbers parameters (peers, similar) or their effect. Since the description does not compensate for the undocumented parameters, and the ones it mentions are already clear from the schema, it adds minimal semantic value. Score is below baseline because the missing 40% remains unexplained.

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 it provides 'side-by-side notable packs for two slugs' and explicitly differentiates from the sibling tool notable_pack by saying 'One call instead of two notable_pack.' The verb 'compare' is implied in the title and the example (elon-musk vs steve-jobs) makes the purpose unmistakable.

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?

It explicitly states when to use this tool: 'One call instead of two notable_pack,' which is a direct alternative to a sibling. The example provides a concrete use case, and the cost mention ($0.08) gives practical context. No exclusionary conditions are given, but the substitution guidance is strong enough to qualify as explicit.

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