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

With no annotations, the description carries the full burden and does well: it discloses the free tier limit (3 calls/hour/IP, shared with the website), the paid path ($0.009 per call over x402 at /v1/chain), and the output stance ('facts and flags only, never advice'). It does not state the return data shape, which is the remaining gap.

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 core purpose, then output stance, then cost/access. The pricing sentence is dense but directly relevant to invocation decisions.

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 the description must cover returns; it names the time windows and the 'facts and flags' nature of the output and covers rate limits and paid access. An agent can call it correctly, though it does not specify the metric's format or edge cases for dead/illiquid chains.

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% and the single 'chain' parameter is documented as DefiLlama chain naming, so the schema does the work. The description adds no naming or format detail beyond it, which is the baseline case.

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 resource (chain) and the exact signal it derives: TVL trend over 1y/6m/90d/30d, framed as a liveness check. It is distinguishable from siblings like safety or stable, though it never explicitly names an alternative.

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 question form ('Is this chain alive') implies the calling context, and the rate-limit/pricing note tells the agent about cost constraints. There is no explicit when-to-use versus siblings such as safety, so guidance is only implied.

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