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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is covered. The description adds real consequence detail beyond that: addresses stop receiving mail immediately (immediacy/irreversibility of impact) and the shared domain is protected. It stops short of stating auth requirements or whether deletion is reversible/undoable.

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?

Three short sentences, zero waste, with the action front-loaded and the two most decision-relevant facts (immediate mail cutoff, shared-domain protection) placed immediately after.

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?

An output schema exists so return values need no explanation, and the destructive annotation plus the description's impact statement cover the mutation's risk profile. Minor gap: no mention of cascading effects on stored inbound messages or whether the action is reversible.

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% and both parameters (id, context) are fully documented in the schema, including a detailed usage note for context. The description only restates 'by id', adding no syntax or format detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb and resource ('Delete a custom inbound domain by id') and scopes it to custom domains, which cleanly distinguishes it from siblings like inbound_domains_list, inbound_domains_create, and inbound_addresses_delete.

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 gives the operative condition for the tool — deleting a custom domain — and adds a clear exclusion: the shared {slug}.in.senderkit.email domain cannot be deleted. It does not explicitly route the agent between deleting a domain versus deleting individual addresses, but the context is unambiguous.

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