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

Annotations already declare read-only, idempotent, non-destructive behavior, and the description goes beyond them with ordering ("newest first"), the implicit 90-day default window, pagination caps, and — most valuably — the `warnings` array explaining that some banks may fail to contribute and may include a `reconnect_url`. That partial-failure disclosure is real behavioral context an agent could not get from the schema.

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?

Four dense sentences with the scope and ordering front-loaded, followed by the non-obvious filtering rule, pagination defaults, and the response caveat. Nothing is redundant with the title and every sentence carries information the agent needs before or after the call.

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 7-parameter read tool with no output schema, the description covers the gap well: it lists the returned fields (ticker, quantity, price, amount), the ordering, the default time window, pagination behavior, and the `warnings` structure. An agent can call this correctly and interpret the response without further documentation.

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%, so the baseline is 3; the description still adds cross-parameter meaning the schema does not state — that dividends surface as type "cash" with subtype "dividend", which tells the agent how two separate filters must be combined. Pagination and date defaults restated in the description largely duplicate what the schema already documents.

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 opens with a specific verb and resource ("List investment account activity") and immediately enumerates the coverage (buys, sells, dividends, cash events, fees, transfers), which makes the investment-only scope unmistakable. It never names the more generic `list_transactions` sibling, so the differentiation from that tool is left implicit.

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?

It supplies useful operating context — the default 90-day window and the limit/offset defaults — so an agent knows what it gets without passing filters. However, there is no explicit when-to-use/when-not guidance and no routing to `list_transactions` or `list_holdings` for non-investment or position-level queries; usage must be inferred from the scope statement.

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