enable_sender_domain_inbound

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

Without annotations, the description carries the burden. It explains that inbound is enabled, replies route through run402, and returns an MX record. Missing explicit mention of whether this is a mutation (changing settings) or a read operation, and no mention of reversibility or authorization.

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?

Two sentences, no wasted words, front-loaded with purpose. Every sentence adds value: what it does, how replies route, requirement, and output.

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 the tool's simplicity (2 params, no output schema, no annotations), the description is nearly complete. It covers the action, prerequisite, and expected output (MX record). Minor gap: does not mention that the domain must be registered first, but is implied by 'verified'.

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% with descriptions for both parameters. The description adds context (verified custom domain) but does not add new details beyond what the schema already provides, matching the baseline.

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 enables inbound email on a verified custom sender domain, with specific verb and resource. It distinguishes from siblings like disable_sender_domain_inbound and register_sender_domain by focusing on enabling after verification.

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?

It mentions a prerequisite (DKIM-verified domain) and a post-action step (add MX record to DNS). However, it does not explicitly state when to use this vs. alternatives like register_sender_domain, though the context implies prior registration.

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