Get PnL History

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

Annotations already declare readOnlyHint=true, so the description doesn't need to repeat that. It adds value by disclosing the return format ('snapshots with realized/unrealized P&L breakdown'). No contradictions with annotations are present.

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?

The description is two sentences totaling 24 words. It front-loads the action and resource, then adds a brief behavioral detail. Every sentence earns its place without 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 simple read-only tool with two optional parameters, the description adequately covers the return value ('snapshots with realized/unrealized P&L breakdown') and purpose. No output schema exists, so this return description is important and is provided. Minor gaps like units or exact snapshot format are acceptable given the tool's simplicity.

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 itself adds no parameter-specific meaning, but both parameters are fully documented in the schema (days with range, interval with enum/default). Thus the description doesn't need to compensate.

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 uses a specific verb 'Retrieve' with a clear resource 'time-series portfolio P&L data' and a stated purpose 'for charting performance over time.' It also mentions the realized/unrealized breakdown, distinguishing it from sibling tools like get_pnl_by_trader or get_pnl_by_market by focusing on portfolio-level data.

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?

The phrase 'for charting performance over time' provides clear context for when this tool is appropriate. While it doesn't explicitly mention alternatives or exclusions, the context is sufficient for an agent to understand its primary use case, especially given sibling tool names.

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