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

Annotations only declare the mutation/safety profile, and the description goes well beyond them: credentials are encrypted at rest and used solely for broker auth, plan caps (FREE 1 / PLUS 3 / TRADER 5 / MAX 20), the MetaTrader 30-day swap rule and its 3 USD fee, MetaTrader provisioning taking 1-3 minutes, and IP-restriction guidance for Binance/Bybit keys. That is exactly the operational context an agent needs before a non-idempotent, non-reversible creation.

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 and platform list are front-loaded, followed by routing and constraints in a logical order. It is dense rather than padded, though the plan/account limits and MetaTrader quota are stated twice (once here, once in the brokerType schema), which is the only real redundancy.

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 non-idempotent creation tool with no output schema, the description covers the plan limits, the credential handling model, the excluded platforms and the correct next step (test_broker_account). An agent has everything needed to call it correctly and verify the result.

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 100% and already documents all eight parameters in detail, so the baseline is a 3. The description still adds value by telling the agent to confirm the account number, master password and server with the user first, and by pointing out that a changed password/server on the same account is free via update_broker_account, which shapes how the parameters should be supplied.

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?

Opens with a concrete verb+resource ("Connect a new broker account to TraderWAI") and immediately enumerates the supported platforms, so the agent knows exactly what this creates. It also draws hard boundaries against update_broker_account, connect_ctrader and tastytrade, which are the siblings that could plausibly be confused with it.

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 names the alternatives and the condition that selects each: same-account password/server changes go to update_broker_account, cTrader goes to connect_ctrader (OAuth), tastytrade goes to the website. It also states the pre-conditions (confirm account number, master password and server before adding; prefer the account they will actually trade) and prescribes a follow-up with test_broker_account.

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