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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context by stating that a NullClear-protected Zero-Loss Proxy URL is returned for each endpoint, which matters given there is no output schema. It still omits pagination/result-count behavior.

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 sentences, no filler, with the core purpose front-loaded and the return-value detail in the second sentence. Every clause earns its place.

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 usefully explains what comes back (per-endpoint Zero-Loss Proxy URLs), and all five parameters are documented in the schema. It stops short of covering result ordering, pagination, or empty-result behavior, but nothing critical to a correct call 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% at five parameters, so the schema fully documents query, category, minUptime, maxLatencyMs and verifiedOnly. The description maps loosely onto the first four but adds no syntax, ranking or range detail beyond the schema, making the baseline 3 correct.

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 gives a specific verb+resource: search the live NullClear Ecosystem Directory for audited x402/ERC-8004 APIs, with the filter dimensions named. It is clearly a discovery/listing tool distinct from operation tools like nullclear_escrow_x402_call, though it never names a sibling to sharpen that distinction.

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: an agent should reach for this to find endpoints before invoking them. However, there is no explicit when-to-use statement, no when-not, and no pointer to the sibling that actually performs the x402 call, leaving the routing to inference.

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