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

Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds that the tool computes aggregate stats and supports optional filters, but it does not describe any additional behavioral traits such as exactly which stats are computed or how period affects results.

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 one concise, front-loaded sentence that immediately states when to use the tool and what it does. No filler or redundant restatement of the tool name.

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?

Given this is a simple read-only aggregation tool with two optional parameters, a rich input schema with enums and defaults, and an output schema, the description is sufficient. It tells the agent what the tool offers and how the optional filters apply.

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% and both parameters have descriptions (period for closed position stats, source as exchange filter). The description's mention of scoping by source and period is consistent but does not add meaningful semantics beyond an already well-documented schema.

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 clearly identifies the tool as the one for aggregate market stats (positions, PNL, win rate), and the optional source/period scoping adds useful specificity. It doesn't explicitly contrast with sibling tools, but 'aggregate' and the stat types help differentiate it from get_positions, get_my_account, and get_signal_stats.

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 description provides clear invocation guidance: use when the user asks for aggregate market stats, optionally scoped by source and period. It does not name alternative tools or explicitly say when not to use it, so it stops short of full guidance.

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