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

Annotations already establish that this is a read-only, idempotent, non-destructive operation, so the bar is lower. The description adds meaningful context beyond them: the VIP0 tier assumption, the averaging windows, and the inclusion of limits/inventory. It still omits refresh cadence and pagination behavior.

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 dense sentence that front-loads the resource and its measurements, with the carry-trade framing at the end. No wasted words, though the trailing jargon ('two halves of a reverse spot-perp carry') may be opaque without domain context.

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?

With no output schema, the description must communicate what comes back; it does list the key fields (VIP0 rates, averages, limits, inventory, funding). However, it leaves the `limit` parameter and pagination/return shape unexplained, which is a meaningful gap for an agent assembling a call.

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 only 50%: `base` has a terse 'Coin (optional)' and `limit` has no description at all beyond its default and bounds. The description hints that filtering is per coin by saying 'per coin and exchange,' but never explains how `base` or `limit` work, so it does not compensate for the coverage gap.

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 the exact resource (margin borrow rates) and its dimensions: per coin and exchange, VIP0 tier, current plus 24h/7d averages, limits, inventory, and most-negative perp funding. This is far more specific than the title, though it does not explicitly name the sibling tool (funding_rates) it complements.

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 two halves of a reverse spot-perp carry' implies the analysis use case, but there is no explicit guidance on when to use this versus funding_rates, best_opportunities, or pair_breakdown. Usage is implied rather than stated.

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