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

The description adds that it 'Returns DNS records to configure,' which is useful behavioral context beyond annotations (which are all false). However, it does not disclose idempotency, handling of duplicate domains, or any prerequisites like domain ownership verification. Annotations provide no safety profile, so the description carries a moderate burden but is not fully 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 two concise sentences, front-loaded with the primary action and followed by a key return detail. Every word earns its place, with no redundancy.

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 adequately complete: it tells what the tool does and what it returns. It does not detail the exact structure of the DNS records, but that is not critical for invoking the tool correctly. The presence of sibling tools (list, verify) completes the domain workflow context.

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 already fully describes the 'domain' parameter with an example (100% coverage). The description mentions 'custom domain' but does not add new meaning to the parameter beyond what the schema provides. Baseline 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 'Add a custom domain to the project' with a specific verb and resource. It distinguishes itself from sibling tools like scalix_domain_list and scalix_domain_verify by indicating the action is to add, not list or verify.

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 context for use is clear: this tool is for adding a custom domain. It does not explicitly mention alternatives or exclusions, but the sibling tools (list, verify) imply different use cases. This is a clear enough context without needing explicit when-not guidance.

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