List domains

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so the safety profile is fully covered elsewhere. The description's one added behavioral fact is that only domain names are returned, not full records — useful but thin for an open-world account-scoped call.

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?

A single front-loaded sentence with no filler or redundancy. Every word carries information about scope and return content.

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 zero-parameter, read-only list tool with no output schema and full annotation coverage, this is close to sufficient: the agent knows what it returns (names) and that it is safe and idempotent. It could add a note on pagination or whether names include verified/pending status, but nothing critical for correct invocation is missing.

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 tool takes zero parameters, so the schema has nothing to explain and the description correctly introduces no parameter syntax. Baseline for a 0-param tool is 4 since there is no room for parameter-level ambiguity.

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?

Clear specific verb (Lists) plus resource (domains) and scope (all domains on the MXroute account). It distinguishes itself from get_domain by implying a bulk name-only listing, but it never explicitly names a sibling or contrasts itself with list_domain_pointers or list_email_accounts.

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?

Usage is only implied: 'all domains' suggests this is the enumeration entry point, but there is no explicit when-to-use or when-to-prefer get_domain for per-domain detail. No prerequisites or exclusions are stated.

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