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

Annotations already cover readOnly/idempotent/non-destructive, and the description still adds substantial context the agent could not otherwise get: 'ip' is null until the Connector connects, 'ownerNote' is authoritative guidance the agent is told to follow, and 'policy' has three distinct levels (full / allowlist / readonly) with what each permits (no file writes under allowlist or readonly). For a discovery tool that gates all subsequent actions, that behavioral payload is exactly what matters.

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 purpose is front-loaded and the long field enumeration is justified because there is no output schema to carry it. It reads as one dense paragraph rather than cleanly separated sentences, which makes it slightly harder to scan, but every clause carries real information and nothing is redundant.

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 fully carries the burden of explaining return values, and it does: id, name, online status, run-as user, last-seen, country, ip, ownerNote, and the policy enum. An agent has everything needed to call this and to act correctly on the result.

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 baseline is 4; the description correctly spends no space on inputs and instead explains how the returned id becomes the 'host' argument on other tools. That cross-tool note is useful but is not parameter semantics for this call.

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 the servers reachable through Termalin") and then enumerates exactly what is returned, so an agent knows this is the host-discovery entry point. It also positions itself relative to the other tools by saying the returned id is the 'host' argument they take, which implicitly separates it from alerts_list, job_list, and the ssh/sftp tools.

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 closing sentence "Use the id (or the exact name) as 'host' in the other tools" makes clear this is the prerequisite call before ssh_exec, sftp_read, and friends. It does not add explicit when-not-to-use or exclusion language, but with no competing sibling serving the same purpose, the routing is unambiguous.

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