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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds genuine value by explaining what the returned health state means and enumerating the problem codes (gsb_blocked / no_dns / unreachable / ssl_error / null), but says nothing about pagination behavior, default ordering, or result size limits.

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 compact sentence with the resource up front and the enum values packed into a parenthetical; there is no filler and nothing is buried behind preamble.

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 five-parameter, all-optional list tool with 80% schema coverage and no output schema, the description is nearly sufficient — it supplies return-field semantics (health states) that the schema cannot express. The remaining gap is pagination/filtering guidance, which the schema mostly covers.

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 80%, so page, search, healthy and per_page are already documented in the schema. The description adds no meaning to any of the five parameters — notably it does not contrast the `healthy` filter with the `type` enum or clarify that `null` in a health state is distinct from a missing field, leaving the schema to do the work.

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 ("List tracking domains") and adds that each row carries a health state, which separates it from get_domain (single record) and create_domain/update_domain (mutations). It never names a sibling tool, so differentiation is inferred from the verb rather than stated.

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?

No when-to-use guidance, no prerequisites, and no pointer to alternatives such as get_domain for a single domain or list_dns_providers / list_domain_providers for related lookups. The agent must infer that this is the enumeration endpoint purely from the word "List".

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