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

Annotations already declare this read-only, idempotent, non-destructive, and closed-world, so the safety profile is fully covered externally. The description adds useful context about what the label contains and what an empty answer means, but says nothing about result shape or confidence beyond the source provenance list.

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, front-loaded with the core meaning and followed by a usage cue and an edge-case note. The parenthetical source list is dense but each element is informative, so little is wasted.

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?

For a one-parameter lookup with no output schema, the description conveys what the result represents (owner, role, provenance) and how to read an empty result. That is close to complete, with minor gaps around result shape and label reliability.

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% and the single address parameter already documents the required 0x+40 hex format. The description adds no address-specific detail such as case handling or whether non-contract wallets are valid input, 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?

The description states a specific resource and outcome: it resolves who an address on Arc mainnet belongs to, breaking that into project/app, role, and label source. This is clearly distinct from aggregate siblings like arc_apps or arc_ecosystem, though no sibling is named explicitly for contrast.

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?

'Use this when asked whose contract or address something is on Arc' gives a clear triggering condition, and the empty-result guidance tells the agent how to interpret a miss. It stops short of naming an alternative tool for cases where a label is absent, which would have earned a 5.

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