blockrun_defi

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the read-only nature is covered. The description adds valuable operational context: per-call payment in USDC, the base+flat fee structure ($0.001 today, $0.002 reserved), the 402 header for exact charge, GET-only paths, and the note that yields is large and should be filtered client-side. This goes beyond what annotations alone provide.

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?

The description is moderately long but well-structured: it opens with purpose, then covers cost, then lists paths with base prices, then examples, then alternatives. Every sentence carries useful information; nothing is redundant. While it could be slightly more compact, the density is justified given the multiple endpoints and the pricing detail.

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 data-retrieval tool with no output schema, the description covers the essential operational details: endpoints, cost model, examples, and filtering advice. It does not specify response shapes, but for a GET-only data fetch, that is typically not critical for invocation. The inclusion of payment semantics and alternative routing makes it sufficiently 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%, so the baseline is high. The description adds further meaning with concrete examples (e.g., 'protocol/aave-v3', 'prices/coingecko:bitcoin,coingecko:ethereum') and clarifies the path format (endpoint under /v1/defillama/). This enhances the agent's ability to construct valid paths without guessing.

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 states a specific verb ('fetches' implied by 'DeFi fundamentals via DefiLlama') and resource with clear scope: protocol TVL, chain TVL, yield pools, token prices. It explicitly distinguishes itself from siblings blockrun_price and blockrun_dex, so an agent can immediately infer what this tool is for and what it is not.

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?

Provides explicit when-to-use guidance: 'Use blockrun_price (free) for plain spot quotes, blockrun_dex (free) for DEX pairs — this tool is for protocol/TVL/yield fundamentals.' This directly names alternative tools and the conditions that select them, leaving no inference required.

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