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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: it requires a Pro API token (Authorization: Bearer arb_…) and is unavailable on the anonymous tier, which an agent must know before calling. It stops short of describing freshness, caching, or empty-state 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?

The first sentence is well front-loaded and information-dense, but the auth requirement is stated twice in near-identical form ('Needs a Pro account token' then 'Needs a Pro API token (Authorization: Bearer arb_…); not available on the anonymous tier'). That duplication costs space without adding information.

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 carries the burden of telling the agent what comes back, and it does so by listing the hedge groupings. Auth and key-type constraints are also covered. Missing only peripheral details such as ordering, whether empty results are possible, or whether data is live or cached.

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?

The tool takes zero parameters, so there is no parameter surface for the description to explain; the baseline for a no-param tool is 4. Nothing in the description misleads about inputs, and it correctly implies no filtering arguments are accepted.

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?

Names a specific resource (hedged positions across read-only exchange keys) and enumerates the groupings returned: delta drift, distance to liquidation, funding received, issues. That is clear enough for an agent to know what it gets back, though it never contrasts itself with siblings such as basis_trades or best_opportunities (which cover adjacent but different data).

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 implied rather than stated: an agent infers 'call this when you want the user's own positions.' The description adds gating conditions (Pro account, read-only keys only), which is useful, but there is no explicit when-to-use versus when-not-to-use guidance and no named alternative among the 26 siblings.

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