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

Annotations already declare readOnly=true, idempotent=true, non-destructive, so the safety profile is covered. The description adds two things the annotations do not: it is paginated, and it requires an API key — a genuine auth prerequisite. It still does not state page-size limits or ordering semantics.

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?

Two compact clauses with the resource and its paging trait front-loaded, followed by the auth requirement. Every clause carries information, though 'for measuring a strategy' is slightly soft framing rather than operational detail.

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 low-complexity, zero-required-parameter read tool with full annotation coverage, the description supplies the essentials: what the ledger contains, that it pages, and that auth is needed. With no output schema present, the exact record fields are left unspecified, which is the main remaining gap.

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 50%: 'before' is documented as an epoch-ms cursor from next_before, but 'limit' is bare (only a default of 100). The description's mention of 'paging' frames both parameters but adds no format, bounds, or default behavior beyond the schema. Baseline 3 is appropriate at this coverage level.

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 resource — a closed-trade ledger — with paging, and adds the framing that it is the complete record for strategy measurement. This distinguishes it from open-order siblings like paper_orders and paper_positions, though it never names those alternatives explicitly.

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 'the full record for measuring a strategy' implies the use case (post-hoc performance analysis of closed trades), but there is no explicit when-to-use, when-not-to-use, or routing to siblings such as paper_orders or paper_report. Usage is inferable rather than directed.

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