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

Annotations already establish read-only behavior. The description adds useful context: data sources (DeFiLlama + Etherscan), daily updates, historical depth to 2018, and the TVL/APY divergence logic. It doesn't contradict annotations and provides insight beyond the basic safety profile.

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 concise and well-structured: the core return value and key output fields are front-loaded, followed by explicit usage scenarios and update frequency. No wasted words.

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?

With no output schema, the description compensates by listing the key output fields (primary_driver_label, tvl_delta_usd, apy_trend, asset_composition) and contextualizing the score's logic. It gives enough for an agent to select and invoke correctly, though a bit more detail on the history response format would be helpful.

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% with the 'days' parameter fully described including the Gold tier requirement. The description mentions 'history to 2018' which aligns with the parameter but adds no new semantic detail beyond the schema baseline.

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 clearly states it returns a 0-100 DeFi protocol TVL-driver score, with specific output fields and data sources. It distinguishes itself from opaque sibling tools by focusing on DeFi TVL/APY analysis.

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?

It provides explicit when-to-use guidance: 'Call when the user asks why a protocol's TVL, total value locked, liquidity, or yield/APY is changing...'. However, it lacks when-not guidance or named alternatives, so it doesn't fully reach the 5-level.

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