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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds one genuinely useful behavioral detail beyond the annotations: that values are read directly from on-chain aToken and Comet supplies (i.e., live protocol state, not an aggregated/indexed source). It says nothing about refresh timing, rate limits, or how unsupported protocol positions are handled.

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?

A single well-formed sentence with the action, scope, and data source front-loaded and no filler. It is efficient, though the parenthesis-heavy construction packs in detail that could be slightly tighter.

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?

The tool is simple (one optional parameter) and has an output schema, so return-value documentation is not needed. The description covers what is computed, which protocols are supported, and where the data comes from. The main remaining gap is the absence of any routing guidance relative to its many defi.* siblings.

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 100% and the single 'chain' parameter is fully enumerated with a default in the schema, so the baseline of 3 applies. The description adds no format or semantic detail beyond what the schema already provides.

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 ('Calculate'), a specific resource ('total value locked (TVL)'), and even names the protocols and data sources ('Aave V3, Compound V3... aToken and Comet supplies'). This is far more specific than a tautology. It stops short of distinguishing itself from defi.liquidity or defi.health, which could plausibly overlap.

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 never states when to use this tool versus alternatives such as defi.liquidity, defi.aggregator, or defi.health, and offers no exclusions or prerequisites. Usage is only implied by the nature of the calculation, leaving the agent to infer routing among eight defi.* siblings.

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