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

Annotations already establish that this is a safe, read-only, idempotent operation. The description adds useful behavioral context beyond that: results are net after fees and slippage, use a live pair, and optionally apply user-supplied funding-rate assumptions per leg.

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 a single efficient sentence with the core calculation and key optional behavior front-loaded. Every clause contributes useful information without repetition.

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 calculation tool with a nested parameter object and no output schema, the description explains the input scenario and holding periods but does not describe the returned result structure or pair_key expectations. It is adequate but leaves some completeness gaps.

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 67%, so some description support is needed. The description meaningfully explains assumed_rates_pct as percent per funding period keyed by instrument_id, but it does not clarify pair_key format and only indirectly covers notional via the schema default.

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 states the calculation: net after fees and slippage for one live pair across specific holding periods. It identifies the resource and scope well, but does not explicitly differentiate itself from related sibling tools such as pair_breakdown or execution_cost.

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?

It implies scenario comparison by listing holding periods and optional custom funding rates, but gives no explicit guidance on when to use this versus alternatives. There are no when-not conditions or sibling references.

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