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

Annotations already declare destructiveHint=false, idempotentHint=true and openWorldHint=false, so the safety floor is covered; the description adds real value by naming the protocol-rule validation step, the artifact produced (preview + pre-filled external Sell link), and the token-holding prerequisite. It does not repeat annotation text mechanically. Minor tension: readOnlyHint=false implies possible state effect while the text stresses "never sends" — an agent may wonder whether any server-side draft/pending record is created.

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 core sentence is front-loaded and well built, but the closing two sentences ("Does not send anything." / "Prepares only; never sends.") say the same thing a third time in a very short description, which is wasted space that could have documented fillWindow.

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?

No output schema exists, so describing the return value was mandatory and is handled (preview plus pre-filled link), and the prerequisite is covered. Gaps remain for a 6-parameter tool: no explanation of fillWindow or expiry defaults, no statement of which chain/protocol the rules come from, and no indication of what a validation rejection looks like.

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 description coverage is 0%, so the description must carry parameter meaning, and it does partially: it assigns ETH units to strikePerToken and premium and identifies token, amount and expiry as validated inputs. However fillWindow (one of six parameters) is never mentioned, nor is expiry's default of "1w" or the meaning of the two enum sets, leaving a meaningful compensation gap.

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?

"Prepare a covered call" pairs a specific verb with a specific instrument, then spells out exactly what it does: validate the five economics of the trade and return a preview plus a pre-filled kyte.sh Sell link. An agent can tell this apart from prepare_buy or prepare_cash_secured_put purely from the description.

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?

Clear operating context: this is the pre-trade validation/preview step, not execution ("prepares only; never sends"), and a hard prerequisite is stated ("The seller must hold the tokens"). It stops short of naming a sibling as the alternative for non-covered-call flows or saying what to do when validation fails.

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