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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context beyond the annotations: a $0.10 USDC cost and the fact that x_api_key or payment_signature unlock a full unmasked dataset, which matters for output fidelity. It stops short of describing what the masked default returns.

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 content is packed into a couple of dense sentences that are front-loaded with the core capability. The opening marketing-style phrase ('Complete Multi-Chain Whale Portfolio & DeFi Yield Optimizer Report') is somewhat verbose, but overall there is little wasted text.

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 carries the burden of conveying what the agent gets back, and it does summarize the pipeline (profiling, pool matching, yield projection) plus payment gating. It lacks detail on the report's structure and the difference between masked and unmasked payloads, but it is sufficient to call the tool correctly.

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 all three parameters are already documented in the schema, including the optional key and payment signature. The description's only added semantic value is the $0.10 USDC cost tied to payment_signature, so the baseline 3 is appropriate.

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 specific actions on a specific resource: profiling a 0x wallet across four named EVM chains, matching idle USDC/ETH against DeFiLlama yield pools, and computing projected annual yield. It is clear what the tool does, but it never distinguishes itself from overlapping siblings like wallet_profiler or defi_yields, so an agent cannot tell them apart from this text alone.

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?

Usage is implied by the framing (profile whale wallets and find yield opportunities), and the mention of masked vs unmasked datasets hints at a paid tier. However, there is no explicit when-to-use, when-not-to-use, or comparison against alternatives such as wallet_profiler, so the agent must infer selection.

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