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

With no annotations, the description does carry weight and does disclose two genuinely useful behavioral facts: the upstream data source (DefiLlama) and a per-call cost of $0.22 in USDC on Base via x402, which tells the agent payment/auth is required. It omits what happens on unknown pools, whether results are cached, and what the response looks like, leaving real gaps for a zero-annotation tool.

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?

Two short sentences and the core purpose is front-loaded, which is good. However, 'Quick screening Price: $0.22 per call' is punctuationally garbled and reads as two fragments merged, slightly reducing scannability of the cost information.

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 simple one-parameter read tool with no output schema, the description covers purpose, source, and cost, which is the minimum an agent needs to call it. It does not indicate what the return contains (APY fields, TVL, chain granularity) or failure behavior, so it is adequate but not complete.

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% with a single 'query' parameter, so the baseline is 3. The description's 'any protocol/pool' wording confirms the free-text intent and matches the schema, but adds no format, matching, or disambiguation guidance beyond it.

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?

The description names the exact resource (APY/TVL) and the data source (DefiLlama) for any protocol/pool, which is concrete enough to distinguish it from the risk-oriented siblings (defi-risk-basic, defi-risk-deep). It stops short of an explicit differentiator such as 'raw yield data, not risk scoring', so it is clear but not exhaustively differentiated.

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?

'Quick screening' implies a lightweight, fast-check use case, hinting that this is the shallow option versus defi-risk-deep. However, it never states when to prefer this over the risk tools, nor any preconditions (e.g., protocol must exist in DefiLlama). Usage is implied rather than spelled out.

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