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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior. The description adds genuinely new behavioral context: the 15-second cache cadence, the on-demand refresh path, and the `ready` precondition. It does not say what error surfaces when the account is not ready.

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?

One dense sentence followed by a concrete example, with the return contents front-loaded. Every clause carries information, though the sentence is packed tightly enough that the refresh mechanics take a second read.

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, return values need no explanation, and the description covers cadence, freshness, and the readiness precondition. The main gap is failure behavior when the account is offline or not ready.

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%, so the baseline is 3. The description goes slightly beyond by restating the fresh semantics in context and by adding the `account must be ready` precondition tied to that flag, plus a concrete example invocation.

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 the exact resource and every returned quantity (balance, equity, margin, free margin, margin level), plus the representation (decimal strings in account currency). This is specific enough to distinguish it from siblings like get_account_overview or get_account_status.

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?

Explains the polling cadence ('read every 15 s while online') and tells the agent to set fresh to force a terminal read, with the precondition that the account must be `ready`. It does not name a sibling alternative (e.g. get_account_overview) to route against, so it falls 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.