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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds one genuinely useful behavioral caveat — reference premiums are only meaningful 'while the spot market trades' — but says nothing about staleness, update cadence, or how a missing/undefined premium is reported.

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 core sentence is front-loaded and dense with concrete asset pairs, with the caveat parenthetical placed inline where it matters. The trailing 'kind: all, reference or peg' fragment is redundant with the schema enum and could be dropped without loss.

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 one-optional-param read-only analytics call this is close to sufficient, and the asset-pair enumeration removes most ambiguity. With no output schema, however, the description leaves the return shape unstated — whether premiums are percentages, basis points, signed, or how a pegged stablecoin deviating from $1 is expressed.

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 the enum's own description fully maps reference/peg/all, so the baseline is already met. The description's closing 'kind: all, reference or peg' restates the enum without adding semantics, so it neither helps nor misleads.

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 a specific analytical resource — the gap between Canton DEX prices and outside reference markets — and enumerates the exact pairs covered (CBTC/BTC, cETH/ETH, eXAU/eXAG vs spot, CC, stablecoins vs $1). An agent can distinguish this from generic siblings like market_overview or spreads without opening the schema.

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?

Usage is only implied: an agent infers this is for checking premium/discount on wrapped or pegged assets. There is no explicit when-to-use, no when-not-to-use, and no named alternative among siblings (e.g. spreads or token) for a related question.

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