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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions 'Read live from the chain' (implies read-only) and discloses the tool is free with a 200-calls-per-day limit. It also enumerates exactly what it checks, giving the agent a clear picture of the tool's behavior. It doesn't describe the return format (since no output schema exists), but it gives enough context for an agent to understand side effects and constraints.

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 description is a single, dense sentence that front-loads the use-case and enumerates checks. Every clause adds value: the trigger, the list of checks, the live-chain read, and the rate limit. No wasted words, well-structured for scanning.

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 tool with reasonable complexity (proxy, owner, token checks) and no output schema, the description gives enough for an agent to decide when to call it. It states the tool is Arc-specific, what it inspects, and its limits. The main gap is the absence of return-format details, but since no output schema exists, an agent can infer the output from the listed checks. It's sufficiently complete for selection and invocation.

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?

The schema already describes the 'address' parameter as '0x contract address on Arc' with 100% coverage. The tool description refers to 'a contract on Arc' but adds no additional syntax, format, or constraints beyond what the schema provides. Since schema coverage is complete, the baseline of 3 is appropriate—the description doesn't meaningfully enrich the parameter semantics.

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 explicitly states the tool's purpose: verifying that an address is a real contract, checking for proxy upgradeability (EIP-1967 implementation, admin, beacon slots), identifying the owner, and determining the token it claims to be. This is a specific verb-resource combo that clearly distinguishes it from siblings like arc_impostors or arc_exit_check.

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?

The description opens with 'Before you approve, pay or trust a contract on Arc', which gives a clear contextual trigger for when to use the tool. It doesn't explicitly name alternative tools or state when NOT to use it, but the context is sufficient for an agent to infer appropriate use cases. A slight improvement would be naming specific alternatives, but it's already clear.

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