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

Annotations already signal read-only and closed-world behavior. The description adds valuable behavioral detail: uncovered tickers return an error, the data is model estimates only and not advice, and the payload is explicitly matched to a public API endpoint. This goes beyond the 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 front-loaded with the core purpose, then details the return payload, then states error and disclaimer caveats. Each sentence earns its place, though the long field enumeration is dense and could be slightly better structured.

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 effectively compensates by listing all returned fields, the error condition for uncovered tickers, and the advisory caveat. For a single-parameter read-only tool, this provides everything an agent needs to call it correctly and interpret the result.

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 input schema covers 100% of the parameter meaning with a clear type and example ('NVDA'). The description adds little beyond reaffirming 'one ticker', so the baseline of 3 is appropriate: the schema carries the parameter documentation burden.

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 names a specific verb ('get') and resource ('a stock's model valuation'), and defines the scope as 'one ticker'. It enumerates the exact fields returned, making the tool's function unambiguous and clearly distinct from sibling tools like list_sector_stocks or search.

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 clearly implies the tool is for retrieving valuation data for a single ticker, and the error condition for uncovered tickers adds useful context. However, it does not explicitly state when to prefer this tool over siblings, nor does it provide any when-not-to-use guidance or alternative routing.

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