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

Annotations already declare readOnlyHint and idempotentHint, but the description adds real behavioral context beyond them: it spells out the returned sections and discloses a sanitization rule ('A description carrying instructions aimed at agents is withheld'), which is a non-obvious trait an agent needs to interpret the results. It does not cover failure behavior for unknown names, so it falls short of full disclosure.

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 core statement is front-loaded and waste-free, but it is delivered as a single sprawling sentence with a nested parenthetical enumerating tool fields, which makes it harder to scan. It could be split into a purpose sentence and a returns sentence without losing information.

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?

With no output schema, the description carries the burden of explaining the return shape and does so thoroughly across registry entry, addresses, tests, tool listings and warnings. Gaps remain around not-found behavior, the untranslated 'language' parameter, and whether large tool lists are truncated.

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 50%: the required 'name' is documented in the schema with the registry format, and the description never repeats or extends it. The 'language' enum parameter is undocumented in both schema and description, and the description does nothing to compensate for that gap or to explain how language affects the returned content.

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 uses a specific verb-and-resource framing ('Everything Horizontal knows about one server') and enumerates the payload (registry entry, addresses, last tests, listed tools, warnings, tried usage patterns), so an agent immediately knows this is the detail-fetch counterpart to search_services. It stops short of naming the sibling explicitly, but 'one server' versus a search tool makes the distinction inferable.

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: the schema says the name comes 'from search_services', which suggests the search-then-fetch workflow, but the description itself contains no explicit when-to-use or when-not-to-use statement. An agent must infer that this is the drill-down call rather than being told.

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