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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's value is in return-shape behavior: empty string vs null semantics for both fields, the '|'-joined newest-first series alignment, and an explicit warning not to interpret an unlabelled figure. It does not discuss rate limits or permissions, but for a closed-world read tool that is minor.

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?

Purpose is front-loaded in the first clause, then the payload structure follows. The very long positional-array enumeration is dense but each field label genuinely aids parsing a schema-less output; only the trailing months-alignment example feels slightly over-specified.

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 correctly carries the return-shape burden and documents both returned structures, including null/empty failure modes. It is nearly complete for call correctness; only guidance on which alias parameter to prefer is absent.

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 three parameters (symbol plus two aliases) are fully documented there, so the baseline is 3. The description adds nothing about parameter usage or alias precedence, but it does not need to carry that 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?

States a specific verb and resource plus the two data families returned ('yearly dividend totals and mutual fund holdings'). It also names the sibling it is not (get_stock_events for dated individual dividends), so an agent can route without opening another 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?

Explicitly directs the agent to get_stock_events with type "corporate_actions" for dated individual dividends, which is the key ambiguity for this tool. It gives no guidance against other nearby siblings like get_shareholding or get_stock_deals, so it is clear but not exhaustive.

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