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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds real context beyond them: the verdict comes from a fixed published rule, the AI-analysis section only appears when a stored analysis exists (conditional behavior), and the tool deliberately withholds buy/sell recommendations. Good disclosure of a non-obvious behavioral constraint.

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?

Usage triggers are correctly front-loaded before the description of returned content. The second sentence is long and comma-heavy but every clause names a distinct output component, so little is wasted.

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?

There is no output schema, so the description carries the return-value burden and discharges it well by enumerating each displayed metric and the conditional AI-analysis section. An agent knows what to expect back and how to frame the result to the user.

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 description coverage is 100% and the single 'stock' param already documents ticker/company-name formats with examples, so the description need not repeat it. It adds no additional parameter semantics, making the baseline 3 appropriate.

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 and resource ('Shows invest-like's answer to Is it undervalued?') and enumerates exactly what the answer contains (P/E vs peers, price to FCF, earnings yield, sales growth). It is clearly distinguished from siblings like explain_stock or compare_stocks by being a valuation verdict on a single stock.

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?

Opens with an explicit trigger list ('good buy, worth buying, undervalued, overvalued, cheap, expensive, worth it') that maps user phrasing to this tool, and adds a clear exclusion ('never says buy or sell'). It does not name which sibling to use for adjacent needs (e.g. explain_stock for a plain explanation), so it falls just short of a 5.

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