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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds value by disclosing the kind of data returned, but says nothing about freshness/caching of fee values or whether the dynamic multiplier changes over time — context that matters for a cost-estimation tool.

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?

Two sentences, front-loaded with what is returned and followed by the intended use. No filler, no restatement of the title, and every clause carries 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 input parameters and no output schema, the description carries the burden of describing return values, and it does list the main components. A minor gap remains: it does not indicate the shape of the per-asset result (keyed by asset symbol, ordering) or whether all assets are always present.

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 no parameters, so there is no parameter semantics to explain; baseline applies. The description instead spends its words on output content, which is the relevant information for a zero-arg getter.

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 verb and resource ("Returns outbound fee information") and scopes it to "all assets," then enumerates the payload fields (fee amount, surplus/deficit tracking, dynamic multiplier). No sibling tool in the list deals with fees, so it is distinguishable in practice, though the description never names a sibling to contrast against.

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?

"Use this to estimate transaction costs" gives a clear, concrete application context for when to call it. There are no explicit exclusions or named alternatives, but with zero parameters and no overlapping sibling, the use case is effectively unambiguous.

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