host_list

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds substantive behavioral details: it returns a list of dicts with specific fields (name, url, read_only, tls, default), explains that the `default` entry is the omitted-host fallback, and describes resolution behavior for single vs. multiple hosts. There is no contradiction with annotations.

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 dense but efficient. Each sentence earns its place: the first states core purpose, the second explains host selection nuance, the third explains the default behavior and gives an example, and the fourth documents the return format. It is front-loaded with the most important 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?

For a zero-parameter read-only list tool with a documented output schema, this description is complete. It covers behavior in edge cases (unset variable, single vs. multiple hosts), return structure, and integration with other tooling. No critical information is missing.

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 has no parameters, so the schema already fully covers parameter semantics (trivially). The description adds value by explaining how the output relates to the concept of a `host` argument even though this tool itself takes no parameters, which helps an agent understand how the returned names map to other tools. However, since there are no parameters to describe, a score of 4 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 starts with a clear verb+resource: 'List the Docker hosts configured via DOCKER_MCP_SERVER_HOSTS.' It distinguishes itself from other list tools by focusing specifically on Docker hosts, not containers, volumes, or networks. It also explains the relationship to the `host` argument, which further clarifies its purpose.

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 description provides pretty clear usage context: it explains how this tool behaves with a single host vs. multiple hosts, how the `default` entry works, and how to use it with daemon-backed tools like `system_ping(host=...)`. It does not explicitly name alternatives or say 'use this when you need X', but the context is strong enough for an agent to infer when to invoke it.

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