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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine context beyond them: this aggregates account state plus the largest positions and their aggregate P/L in a single call, and that 'top' defaults to 5. It does not mention whether the account must be online (bring_accounts_online exists as a sibling) or any rate behavior.

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?

Three short sentences, front-loaded with the payload summary, then the routing cue, then a call example. Nothing is padded and nothing is repeated from the schema beyond the minimal example.

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 an output schema present, the description need not document return fields, and it correctly avoids doing so. It is complete for input and purpose; the only real gap is operational state — a hint about account-online prerequisites or what happens if the account is offline would close it out.

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 account_id, top, and response_format are all fully documented in the schema — baseline 3 applies. The description's 'largest open positions' hints at the top parameter and its example confirms the account_id key, but adds no format, bound, or uuid-vs-login detail beyond what the schema already states.

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 concrete resource ('one account in one call') and enumerates its payload: state, environment, balance and equity, top open positions with total P/L. That is far more specific than a bare 'get account', though it never names the sibling tools it overlaps with (get_account, get_account_figures, get_account_status), leaving the agent to infer the split.

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?

'Start here when asked how an account is doing' gives a clear entry-point condition, which is real routing guidance against a 29-tool sibling set. It stops short of explicit exclusions (when to prefer get_account_status or get_account_figures instead), so the agent knows when to use it but not when not to.

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