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

Explicitly discloses wholesale field replacement, empty-value-clearing behavior, root 404 default, and immutability of hostname. Aligns with destructiveHint and enriches the annotation with operation-specific side effects.

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?

Well-organized and every sentence carries useful information, but the final hostname/no-delete clause is slightly convoluted and the front-door framing adds length. Still far from padded.

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?

Covers all parameters, constraints, mutations, and relationship to deletion via the Tessryx app. Output schema exists, so not explaining return values is acceptable. Complete for correct invocation.

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 already covers all parameters 100%, and the description adds meaningful clarifications: display_name empty clears it, slug_prefix empty maps to whole tenant tree, root_endpoint is relative to slug_prefix, and hostname is identifying and immutable.

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?

Clearly states it updates a custom domain's mutable settings (display_name, slug_prefix, root_endpoint) and explicitly notes hostname is immutable. Distinguishes from deletion/creation by stating domains cannot be deleted via these tools, so the action is unambiguous.

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?

Provides concrete routing semantics and examples (set slug_prefix to app slug prefix), and notes destructive/delete actions occur in the Tessryx app. Does not explicitly name create_custom_domain or verify_custom_domain as alternatives, so guidance is strong but not exhaustive.

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