is_contract

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

No annotations are present, so the description must handle behavioral transparency. It implies a read-only query but does not specify error behavior for invalid addresses or network constraints. The return format (e.g., boolean + number) is not explicitly documented, which is a key behavioral 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?

The description is a single short sentence that efficiently conveys the tool's core function. It is front-loaded but could include additional detail without being verbose.

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?

Despite the tool's simplicity, the description fails to specify the output format (e.g., boolean and integer? object?) and does not address error cases. With no output schema, this lack of clarity makes the tool incomplete for an AI agent to use correctly.

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 description adds meaning to the single 'address' parameter by indicating it is the address to check. With 0% schema description coverage, this is helpful but still lacks details like checksum requirements or accepted formats.

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 clearly states that the tool checks if an address holds contract code and provides information on how much code it holds. This identifies the tool's purpose and differentiates it from simpler balance or nonce checks. However, the phrasing 'how much' is somewhat ambiguous (e.g., bytecode size in bytes).

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?

No guidance is provided on when to use this tool vs. siblings like contract_source or read_contract. The description does not mention typical use cases or prerequisites, leaving the agent to infer usage from context.

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