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

Goes well beyond the annotations: it discloses that an approval step may be inserted, that both caps are checked, that the result is UNSIGNED calldata (to, data, value, gas), that it is simulated against the latest block and refused on revert, and that it never signs or sends. These are exactly the behavioral facts an agent needs and none are in the annotation set.

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?

Four tight sentences, zero filler: action first, then guards, then return shape, then the safety boundary. Every clause carries information the agent would otherwise have to guess.

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 no output schema, the description correctly describes the return payload (to, data, value, gas) and adds the failure semantics (refused if simulation reverts). Nothing needed to call or interpret this three-parameter tool 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 the baseline is 3; the description still adds meaning by framing amount as the deposit input and noting that both caps are checked against it, telling the agent that an out-of-range amount will fail rather than silently clamp. Minor value-add over the schema, hence 4 rather than 3.

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 concrete verb and resource ('Add collateral to an existing position') plus the underlying call sequence (approval then deposit). The phrase 'for the user's own wallet' implicitly separates it from the prepare_mandate_deposit sibling, so an agent can place it in the family without opening the 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?

Usage is implied by 'add collateral to an existing position', which tells the agent the position must already exist, but there is no explicit 'use this instead of prepare_mandate_deposit / prepare_create_position' guidance. With 22+ siblings including a near-duplicate mandate variant, the missing routing sentence is a real gap.

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