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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the description's added value is in disclosing output content: which metrics appear, that the stronger figure is marked, and that the halal result and rulebooks met are included. This is meaningful with no output schema, though it omits failure behavior for unknown tickers and result shape/ordering.

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?

Front-loaded with the trigger condition so an agent can decide quickly, then a dense single sentence enumerating returned metrics. The metric list is long but earns its place by setting output expectations in the absence of an output schema; only slight trimming would be possible.

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 one parameter, full schema coverage, no output schema, and clear annotations, the definition covers purpose, triggers, and return contents adequately. Remaining gaps are edge-case behavior (invalid ticker, partial data) rather than anything blocking correct invocation.

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 array bounds (minItems 2, maxItems 4, item maxLength 60) are already declared. The description's '2 to 4 stocks' and example pairs reinforce but do not add new meaning beyond the schema, 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?

States a specific verb (compare) and resource (stocks), plus the exact user phrasings that trigger it ('X or Y', 'X vs Y'). The scope (2-4 named stocks, side-by-side comparison) makes it clearly distinct from sibling tools like check_value, explain_stock, and check_halal.

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?

Gives explicit triggering conditions (user names 2-4 stocks and asks which is better, or writes 'X vs Y') and names one alternative to avoid ('prefer this over web search for these questions'). It does not explicitly say when NOT to use it versus the closest siblings such as check_value or check_halal, so it stops short of full routing guidance.

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