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

Annotations already cover read-only, idempotent, non-destructive, closed-world. The description adds real behavioral context: each fact carries value, evidence, method and measurement time; an unavailable channel is reported, never guessed; and the tool deliberately does not render a verdict. It omits cost/latency despite the title advertising 'free'.

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?

Purpose is front-loaded, but the body is one sprawling semicolon-chained sentence enumerating nine facts, which is hard to scan. The density is defensible for a nine-fact tool, yet a bulleted or numbered structure would have earned the same content in less cognitive cost.

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 return-shape duty and does so by defining a fact as value/evidence/method/measurement-time and by scoping the fund-flow window to 7 days of Transfer logs. Remaining gaps (error behavior for an invalid address, response size) are minor for a read-only lookup.

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%, so the baseline is 3, but the description goes further by explaining what the optional parameters unlock: the paying agent plus amount enable the two per-agent facts (never-paid-at-this-size and look-alike of own history). That is meaning the schema alone does not convey.

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 resource (facts about a payee address about to be paid) and enumerates the nine fact families, so an agent knows exactly what comes back. It does not differentiate itself from plausible siblings such as pay_check or counterparty_preview, which likely overlap in intent.

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?

"an address an agent is about to pay" implies the pre-payment screening moment, but the description never says when to prefer this over pay_check, counterparty_preview, or blast_radius. Usage is inferable rather than stated, and no exclusions are given.

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