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

Adds real context beyond the annotations: 'nothing moves yet' clarifies state despite readOnlyHint=false, and the return shape (preview_id, amounts, expires_at) is disclosed. It doesn't cover auth requirements or how long a preview stays valid beyond the expires_at mention, so it stops short of a 5.

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?

Front-loads the step number and purpose, then mode semantics, then the follow-up call. Dense but every sentence carries routing or behavioral information; the parenthetical about USDT crediting is slightly discursive but justifies why the tool exists.

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?

For a 7-parameter mutation-adjacent preview with no output schema, the description covers purpose, mode branching, the no-side-effects guarantee, the returned fields, and the next step. An agent has everything needed to call it correctly and interpret the result.

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 baseline is 3, but the description adds the mode interaction that the schema documents only piecemeal: 'single' converts amount of from_asset_id to USDT or to to_asset_id, while 'all_to_usdt' sweeps every non-USDT holding. It also implies the USDT default for to_asset_id, which is useful cross-parameter semantics.

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 ('Step 1 of converting assets... into USDT') and explicitly positions itself as the preview stage before create_conversion. An agent can distinguish it from create_conversion and preview_payout without opening any schema.

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?

Gives explicit when-to-use context ('this matters only for an account that still holds another asset'), names the alternative for the opposite direction (send a payout via preview_payout), and names the follow-up call (create_conversion). Nothing about routing is left to inference.

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