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

Annotations only declare readOnlyHint=true, so the description carries the rest, and it does add real value: this is a non-executing preparation step gated by a fresh balance read, a preview, and mandatory wallet simulation before authorization. That workflow constraint is not derivable from the annotations. It stops short of stating what the preparation actually emits (unsigned transaction vs. plan object) or whether an approval is needed.

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 tight sentences with the core purpose front-loaded and no filler. The second sentence is dense with prerequisites but still readable; a small loss for jargon ('fresh wallet/RPC balance') that an unfamiliar agent may need to unpack.

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?

An output schema exists, so return values need not be explained, and the schema covers all five parameters. What is left implicit is the transaction lifecycle: whether preparation produces an authorization-ready transaction, whether a separate simulation or submission tool follows, and how approval for the sUSDS shares is handled when owner differs from sender.

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%, so every parameter including owner/receiver defaults and the chain-1 constraint is already documented in the schema. The description echoes 'exact share amount' but adds no semantics about base units, owner/receiver defaults, or the chain restriction beyond what the schema provides, so the baseline 3 applies.

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?

States a specific verb and resource: prepare a direct sUSDS ERC-4626 redemption, scoped to an exact share amount. The 'exact share amount' phrasing implicitly separates it from prepare_sky_savings_withdraw (asset-denominated), but no sibling is named explicitly, so an agent must infer that distinction.

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 second sentence gives procedural guidance (use fresh wallet/RPC balance and preview, require wallet simulation before authorization), which implies when the tool fits into a workflow. However, it never states when to choose this over prepare_sky_savings_withdraw or when not to use it at all, leaving the sibling routing to inference.

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