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

With no annotations, the description carries the full behavioral burden. It discloses one useful trait — daily sampling of realized plus unrealized PnL — but says nothing about permissions/auth requirements, max range, ordering, or pagination of the series.

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?

A single tight sentence with the key qualifiers (realized + unrealized, sampled daily) front-loaded and no padding. It is efficient, though its brevity stems partly from omission rather than deliberate conciseness.

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 4-parameter tool with no annotations and no output schema, the description leaves the agent without the information needed to call it confidently: no return shape for the curve, no valid time-range constraints, and no explanation of subaccount_id's effect.

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 0% across four parameters (from_ms, to_ms, user_id, subaccount_id). The description only weakly implies user scoping via 'for the user' and a time window via 'Historical'; it gives no units, timestamp format, subaccount behavior, or default range.

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?

The description names a specific resource (Historical PnL curve) plus its composition (realized + unrealized) and scope (for the user), so an agent can distinguish it from portfolio_read or orders_history. It does not explicitly name the sibling it differs from, keeping it just short of a 5.

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?

There is no guidance on when to use this versus portfolio_read (current state), orders_history, or positions_list, and no stated preconditions or exclusions. Usage is only implied by the word 'Historical'.

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