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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuine semantic context: the result is split into two categories and scoped by a time window. It does not explain ranking/ordering of shared items or what happens when no overlap exists, leaving a small 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?

Two tightly written sentences: the first defines what is computed, the second routes usage. No filler, and the core definition is front-loaded.

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 does the necessary work of naming the two returned categories, which is what an agent needs to interpret results. It could go further on ordering, empty-result behavior, and default chain implications, but nothing critical to invocation is missing.

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 enum values and defaults documented, so the schema carries the burden. The description reinforces the window concept but adds nothing about chain selection, the limit cap of 50, or address format expectations, so baseline 3 applies.

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 verb (compare) and resource (two wallets) and enumerates exactly what is computed: shared counterparties and shared tokens within a window. The cross-wallet comparison framing inherently distinguishes it from single-wallet siblings like wallet_counterparties and wallet_token_balances.

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 triggering context with quoted user phrasings ('are these two wallets related' / 'what do X and Y have in common'), which is stronger than typical. It stops short of naming alternatives or exclusions (e.g., when to use wallet_counterparties twice instead), so it lands just below a 5.

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