Read E*TRADE transactions

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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds meaningful behavioral context beyond them: E*TRADE retains only two years of history and pages at 50 rows, plus the return shape (table with date, symbol, quantity, price, amount).

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 sentences, front-loaded with what the tool returns before the use cases. Tight and readable, with no redundant filler.

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 read-only annotations and no output schema, the description carries the return-format burden and does so adequately (table columns, retention, pagination). For a filtered-history read tool, an agent has enough to call it correctly.

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 coverage is high (80%), so the schema already explains symbol, count, startDate and accountIdKey semantics. The description only tangentially reinforces the 50-row page cap and two-year limit, adding little parameter meaning beyond the schema. Baseline 3 is 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 ('Transaction history for one E*TRADE account') and enumerates the record types (trades, dividends, transfers, fees) and fields it returns. This clearly distinguishes it from siblings like etrade_positions and etrade_balances.

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?

Provides concrete use cases (reconstructing cost basis, verifying rebalance execution, separating dividend income from realised gains), which tells the agent when this tool is the right choice. It does not, however, explicitly name alternatives or state when NOT to use it.

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