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

With no annotations provided, the description carries full burden for behavioral disclosure. It reveals non-obvious consequences: the transfer takes 5-7 days and adds 1 year to expiry. It also mentions the prerequisite of an EPP/auth code. While it does not cover reversibility or post-transfer management, the core behavior and timeline are transparent.

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 three concise sentences: the main action, the requirement, and the duration/impact. It is front-loaded with the verb and resource, contains no filler words, and every sentence contributes essential information.

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 description is sufficiently complete for a mutation tool of moderate complexity. It explains what happens, the timeline, and the effect on expiry, while the schema covers additional prerequisites (e.g., domain age, unlock status). No output schema exists, but the description gives enough context to understand the outcome. It could mention potential failure reasons, but overall it is adequate.

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 input schema provides 100% coverage with detailed descriptions for both parameters, including conditions for 'domain' and synonyms for 'auth_code'. The description adds no new parameter-specific information beyond restating the need for an EPP/auth code, which the schema already explains. Thus, the baseline score of 3 is appropriate.

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 action with a specific verb ('Transfer'), the resource ('a domain'), and the context ('from another registrar ... to MCPDomain'). This distinguishes it from sibling tools like register_new_domain and configure_domain_dns, leaving no ambiguity about its purpose.

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 implies when to use the tool: when the user has an existing domain with another registrar and possesses the EPP/auth code. It also provides practical guidance by noting the 5-7 day transfer time and the addition of one year to expiry. It does not explicitly list exclusions but the context is clear enough for an agent to select it appropriately.

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