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

Beyond the readOnlyHint annotation, the description discloses that values are model estimates rather than forecasts or price targets, that no confidence interval is returned because none is computed, and that the response carries an app link with fair value drawn on the chart. It also explains the non-numeric branch ('the plain reason there is none'), which is real behavioral context. It stops short of describing pagination/units or what the 'no valuation' reason strings look like.

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 output content is front-loaded in the first sentence and the caveats follow in a logical order, with the read-only note placed last. Minor waste in phrasing like 'the plain reason there is none' and the sentence about opening the company, but nothing is significantly bloated.

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 one-parameter read tool with no output schema, the description covers the return payload (two percentages or a reason), the epistemic caveats, and an extra artifact (app link), which is enough for correct invocation. It could be more complete about failure modes for invalid tickers, but that gap is small.

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 required parameter with 100% schema description coverage ('Ticker symbol, e.g. NVDA'), so the schema already carries the semantics. The description adds nothing about ticker format, symbol resolution, or what happens with an unknown ticker, making this the baseline 3.

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 and resource (get one company's valuation) and enumerates the actual outputs: margin of safety, cash-flow upside in percent, or the reason neither exists. That output enumeration distinguishes it from siblings like get_stock_score or get_core_economic_profit without needing to open the 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 implied by 'one company's valuation' (single-ticker lookup), and it positions itself relative to get_company_snapshot ('Opens the company like get_company_snapshot does'), but that comparison is about behavior, not a routing rule. There is no explicit when-to-use-this-instead-of guidance for the nearby scoring tools (get_stock_score, get_core_economic_profit) and no stated prerequisites or exclusions.

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