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

Annotations only declare readOnlyHint=true, so the description has room to add value, and it does: it discloses the composition of the plan (approve → deposit → allowance cleanup), that the three steps are atomic, and that the vault interface omits minimum-shares and deadline protections. It stops short of saying explicitly that nothing is broadcast on-chain or what the plan output looks like, but the “wallet plan” phrasing is consistent with the read-only annotation.

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 zero filler. The composition of the plan is front-loaded, and the rationale for the mandatory simulation follows immediately as supporting context.

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 an output schema present, return-value detail is unnecessary, and the description covers the multi-step atomicity, token identities, and the missing vault safeguards. The main residual gap is the absence of routing guidance against the many sibling prepare_* tools, though the deposit-specific naming mitigates this.

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 the schema already documents amount, sender, chain_id and receiver; the description only reinforces the “exact” nature of the amount and the approval. It adds no new meaning about the receiver default or the chain-1 restriction beyond what the schema states, so 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?

Names a specific verb (“Prepare”) and a precisely scoped resource: an exact USDS approval, an ERC-4626 sUSDS deposit, and an allowance cleanup bundled as one atomic wallet plan. The deposit framing plus the sUSDS/ERC-4626 identifiers distinguish it cleanly from the sibling prepare_sky_savings_redeem and prepare_sky_savings_withdraw tools without needing their schemas.

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 gives a hard precondition — a fresh preview and exact wallet simulation are mandatory because the vault interface lacks minimum-shares and deadline fields — which is real usage context. However, it never states when to choose this over the sibling redeem/withdraw/approval-revocation tools, nor any exclusions or prerequisites regarding token balances or chain.

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