defi_tvl

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

With no annotations, the description carries the full burden and does disclose two high-value traits: per-call cost ($0.002 USDC) and p99 latency (4000ms), plus a rough sketch of what each mode returns. It omits error behavior, caching/rate limits, and result pagination shape.

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?

One dense, front-loaded paragraph organized as mode: meaning, followed by a compact params and cost/latency line. Every sentence carries information; there is no filler.

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 5-param read tool with no output schema or annotations, the description supplies mode semantics, defaults, cost and latency, which is close to self-sufficient. Return-value structure, error cases, and any per-mode limit behavior are left unstated.

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 only 60%, and the description compensates by explaining every parameter, including the non-obvious conditional default ('default top, or protocol if protocol is given') that appears nowhere in the schema. Chain, category, protocol and limit constraints largely repeat what the schema already states, keeping this short of a 5.

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 the specific resource (DeFi TVL / DEX volume from DefiLlama) and decomposes it into four named modes with the exact metrics each returns. An agent can tell this apart from siblings like defi_yields or crypto_prices 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?

Each mode is paired with the question it answers (protocol breakdown, top rankings, chain rankings, DEX volume), and it documents the default-selection rule for mode. It stops short of naming alternatives (e.g. defi_yields for yield data) or stating when not to use it.

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