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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description still adds value beyond that by disclosing the returned comparison dimensions and the caveat "Informational, not a recommendation," which shapes how an agent should frame the output. It does not mention limits on slug resolution failures or result formatting, keeping it short of a 5.

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?

Three short sentences, front-loaded with the capability and its return set, then the routing rule, then the disclaimer. No sentence is redundant or padded.

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 tool with no output schema, the description supplies the return dimensions, the invocation range, the sibling alternative, and the informational caveat. Nothing an agent needs in order to call it correctly 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?

There is a single parameter at 100% schema coverage, and the schema already documents the 2-5 bound and the ticker-or-slug format. The description's "2 to 5 stocks" restates the schema constraint rather than adding new meaning, so the 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?

The description states a specific verb and resource (compare 2 to 5 stocks side by side) and enumerates what is compared: price, 1-day change, market cap, layers, and AI Exposure Score with rationale. It also explicitly distinguishes itself from get_ticker, so an agent can route between the two 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?

It names the triggering query shape ("X vs Y" questions) and names the alternative with its condition (one stock in depth -> get_ticker). Both the when-to-use and the when-not-to-use cases are covered explicitly.

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