set_primary_name

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

With no annotations, the description carries full burden. It discloses the irreversible replacement behavior ('setting a new one replaces the previous'), permission requirements ('Only the wallet owner can set their own primary name'), and the prerequisite condition on the ENS records. It does not mention return values or gas costs, but the disclosed traits are useful and accurate.

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 a clear purpose statement, a helpful example, and a bullet-like list of requirements. It is slightly longer than necessary but every sentence adds value, and the conditional alternative to set_ens_records is a useful addition.

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?

The tool has only 2 parameters and no output schema, so the description must cover behavior and prerequisites. It does so effectively, including the replacement side-effect and required setup. However, it does not describe the expected return value (e.g., transaction hash) which would be helpful for an agent to confirm success.

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% for both parameters, so the baseline is 3. The description adds contextual meaning about the relationship between the name and wallet (ETH record must point to wallet), but does not provide new syntax or format details beyond what the schema already gives.

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 opens with a specific verb and resource: 'Set the primary ENS name (reverse resolution) for a wallet address.' This clearly distinguishes it from siblings like get_primary_name and set_ens_records by explicitly focusing on reverse resolution.

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?

Provides explicit requirements (ownership, ETH record match, wallet owner only) and an alternative: 'If the ETH address record doesn't match, use set_ens_records first to update it.' Also warns about replacement behavior, giving the agent clear when-to and when-not-to guidance.

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