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

readOnlyHint is already declared in annotations, and the trailing 'Read-only' merely repeats it. The description does add one genuinely useful disclosure beyond the annotations: the response includes an app link to the full comparison, which matters because there is no output schema. Otherwise it omits pagination, any per-ticker failure behavior, or limits beyond the count.

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?

Two short sentences with the scope and count limit front-loaded. The closing 'Read-only' is redundant against the readOnlyHint annotation and could be dropped, but overall it is tight with no padding.

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, fully documented read tool with no output schema, the description covers purpose, scope, and return content (an app link). It stops short of explaining error behavior for invalid tickers or whether unsupported symbols are dropped, which would complete the picture.

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 'tickers' parameter is fully documented in the schema, so baseline 3 applies. The description restates the 'up to 5 tickers' cap but adds no format guidance (e.g., exchange suffixes, casing) beyond what the schema already provides.

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 (Returnolio scores and pillar breakdowns) with an explicit scope of up to 5 tickers side by side. This cleanly distinguishes it from single-ticker siblings like get_stock_score, so an agent can route without opening schemas.

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 'up to 5 tickers side by side' phrasing implies the multi-ticker comparison use case and contrasts implicitly with single-score tools, but it never names an alternative or states when to prefer this over get_stock_score or screen_stocks. Usage is inferable rather than stated.

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