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

Annotations already establish readOnlyHint=true; the description adds meaningful behavioral detail beyond that: negative maker fees are rebates, tiers depend on 30-day volume, staking can affect fees, and the output includes thresholds and the full tier table. It transparently conveys that this is a snapshot-style read of the account's fee status.

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 dense but well-packed: it front-loads the core purpose, then enumerates precisely what the response contains, and closes with one relevant cross-reference. Every clause supports the agent's decision to use or understand the tool.

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 zero parameters, a readOnly annotation, and no output schema, the description covers the needed return values and edge cases (negative fees, staking discounts, progression to next tier, referral handling). Nothing critical is missing for the agent to select and use this tool successfully.

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 exposes no parameters, so there is no schema burden to compensate. The description still contextualizes what the tool inherently applies to—the current account's trading fee tier—which is sufficient for invoking the tool correctly.

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 it returns the account's current trading fee tier and related conditions, with resourceful detail (maker/taker fee, rebates, volume, staking discount, full fee-tier table). It distinguishes itself from siblings by focusing on 'this account's current' fee-specific data and even directs to get_referral_program when relevant.

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 description makes clear when this is the right tool: to learn one's own fee tier and the conditions used to compute it. It also forwards referred users to the specific sibling get_referral_program. It does not provide broader when-not/alternative guidance, but there is no strongly overlapping sibling.

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