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

Annotations already declare destructive/idempotent/openWorld, but the description adds genuinely useful behavior beyond them: the call 'returns at once' (asynchronous dispatch that must be polled via get_multi_account_order), and that it targets real broker accounts or demo. It stops short of 5 because it doesn't state what triggers the all-or-nothing refusal or partial-failure outcomes.

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?

Front-loads the action, then the follow-up call, then the confirmation requirement, then an example. Each sentence earns its place and there is no filler; the embedded JSON example makes the last clause dense but it is directly actionable.

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?

An output schema exists so return values needn't be explained, and annotations cover the safety profile. The description still supplies the confirmation prerequisite and the polling follow-up, making it largely complete for a 14-parameter, high-impact multi-account mutation, though it could note error/partial-fill handling.

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, and the description's concrete example adds value by showing the exact required-parameter shape (account_ids, instrument, side, volume, idempotency_key as a new uuid) in a realistic invocation. It does not add semantics for the optional advanced params (weights, barrier_policy, expires_at), which the schema handles.

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 (places), resource (market order), and a distinguishing scope (the same order on many of the user's real broker accounts at once). The 'many accounts at once' framing separates it from the single-account sibling place_market_order without needing to inspect either 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?

Gives a clear when-to-use context plus an explicit workflow and prerequisite: 'follow it with get_multi_account_order' and 'Confirm the accounts, symbol, side and volume with the user first.' It does not name the single-account alternative (place_market_order) or state a when-not-to-use, so it stops short of a 5.

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