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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the non-mutating nature is covered. The description goes beyond them by disclosing the balance precondition that causes refusal and by interpreting the output ("the gap is what the swap costs"), which is real behavioral context. It doesn't mention quote staleness/expiry, which matters for a live price.

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?

Three short sentences, front-loaded with the price-don't-execute distinction, then output semantics, then the refusal condition. No filler, and the most decision-relevant fact comes first.

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 the description needn't enumerate returns, yet it briefly frames their meaning, and it covers the one precondition an agent could trip over. For a read-only four-parameter quote tool with full annotations, nothing needed for correct invocation is missing.

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 baseline is 3. The description still adds value: it ties slippage_bps to minimumOutputAmount ("the least the swap delivers at the slippage limit") and ties from_mint to a required wallet balance, which the schema does not state.

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 ("Price a swap inside your managed agent wallet") and immediately delimits it with "without making it," which is exactly what separates it from the sibling agent_wallet_swap. An agent can pick between the two without opening either 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?

"Same arguments as agent_wallet_swap" plus "without making it" gives clear implied routing: quote first, execute later with the sibling. The precondition "Refused if the wallet holds less of from_mint than amount" adds a concrete when-it-fails condition. It stops short of an explicit "call this before agent_wallet_swap" instruction, so not a 5.

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