extend_subname_expiry

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

With no annotations, the description carries the full burden for behavioral disclosure. It clearly explains permission requirements (parent owner, subname owner with fuse burned) and a key constraint (subname expiry cannot exceed parent expiry). It doesn't cover error behavior or side effects beyond extending expiry, but it provides substantial useful context.

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 well-structured with clear sections for definition, permissions, and use cases. Every sentence earns its place, and the core action is front-loaded.

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?

Given that there is no output schema, the description covers the essential context: purpose, permissions, constraint, and use cases. It is reasonably complete for a tool of this complexity, though it doesn't specify what happens if the requested years exceed parent expiry or other failure modes.

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%, so the baseline is 3. The description adds the parent-expiry constraint but doesn't meaningfully augment the parameter meanings beyond what the schema already provides.

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 the tool's specific action: 'Extend the expiry of an ENS subname in the NameWrapper.' The verb 'extend' and resource 'ENS subname' are specific and distinguish it from sibling tools like renew_ens_name that likely target parent names.

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 provides explicit who-can-call rules and concrete use cases, giving clear context on when to use the tool. However, it does not explicitly name sibling alternatives or state when not to use it, which would push it to a 5.

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