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

Annotations already establish readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context: it returns only bio data, excludes peer/life-in-days content, and costs $0.02. No contradiction with annotations is present.

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 entire description is compact and front-loaded: core behavior first, exclusions and routing second, then a concrete example and pricing. Every clause earns its place with no redundant filler.

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?

For a single-parameter read-only tool with an output schema and clear sibling routing, the description is complete. It tells the agent what the tool returns, what it excludes, when to use a different tool, and even cost. No critical context for correct invocation is missing.

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 single slug parameter with 100% coverage. The description reinforces that the lookup is by slug and provides a concrete example, but it does not add substantially new semantic information beyond 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 states a specific action and resource: returning a bio-only profile JSON by slug. It explicitly differentiates itself from notable_pack by listing what it does not include (life-in-days, similar, birthday peers), so an agent can immediately understand its narrow purpose versus siblings.

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 explicitly says to prefer notable_pack for 'who is X / age in days / peers', giving a clear when-not-to-use condition and naming the alternative. The slug-based lookup and example 'taylor-swift' further clarify the intended invocation context.

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