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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so safety is covered. The description adds genuine context beyond them: the optional-section model, that 'history' swaps 90 days for 1 year, and an explicit 'Informational, not a recommendation' disclaimer. It stops short of describing response shape or size/rate constraints.

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?

A single dense sentence with the payload front-loaded and the disclaimer trailing. No filler or repetition.

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?

With no output schema, the description does the necessary work of enumerating the returned fields and the opt-in extras. Slightly short of complete because it gives no sense of response size or cost when requesting all sections.

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 coverage is 100%, so both parameters are already documented, including the ticker/slug duality and the enum values. The description only restates the optional sections and the history-horizon effect that the schema already states, adding no new syntax or constraint detail; baseline 3 applies.

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?

States a specific verb+resource ('One AI-buildout stock') and enumerates the payload: price, AI Exposure Score, layers, explainer, 90 days of closes, optional sections. It is clearly the single-entity counterpart to search_stocks/get_layer, so an agent can distinguish it from siblings without opening a schema.

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?

Usage is only implied: fetch one stock by ticker. It never says when to prefer this over search_stocks or get_layer, nor when the optional sections should be requested. No exclusions or prerequisites are given.

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