set_primary_domain

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

With no annotations, the description takes on the full burden of behavioral disclosure. It explicitly states the MCP does NOT build or broadcast the transaction, and that the setting is completed in the browser with wallet signing. This is crucial non-obvious behavior that prevents an agent from falsely assuming the tool performs the mutation directly.

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: it starts with the primary action, explains the browser flow and MCP's limited role, gives trigger examples, and states a prerequisite. Every sentence adds value and there is no unnecessary text.

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 simple one-parameter tool with no output schema, the description is complete for selection and invocation. It clarifies what the tool returns (a link), how the process works, when to use it, and what constraints apply (domain ownership). The absence of a return value schema is mitigated by the clear statement that it 'gets the link.'

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 provides 100% coverage for the single 'domain' parameter with a clear example ('alice.xrp'). The description adds no new semantic details about the parameter, just repeating the concept in the use examples. The baseline for full schema coverage is 3, and the description does not exceed it.

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 'gets the link' to set a domain as primary, with an explicit definition of primary as 'the name shown by default for your address.' It distinguishes this from the sibling register_domain by focusing on the primary-setting action and noting the domain must already be owned.

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 trigger phrases ('make X.xrp my primary', 'set X.xrpfi as my main domain') and a clear prerequisite ('The wallet must already own the domain'). It also explains the tool's role in the broader workflow, which helps an agent decide when to use it.

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