Host identity

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

Annotations already provide readOnlyHint=true and openWorldHint=false, covering the safety profile. The description adds the useful clarification that it targets the 'real host' rather than any remote system. However, it doesn't disclose other potential behaviors like latency or failure modes, which is acceptable given the tool's simplicity and annotation coverage.

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 sentence that states the tool's purpose with zero wasted words. It is front-loaded and immediately comprehensible, with no redundant qualifiers or filler.

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?

This is a zero-parameter, read-only tool with both annotations and an output schema available. The description fully explains what the tool does, and nothing else is needed for an agent to correctly invoke it. The presence of an output schema obviates the need to describe return values in the description.

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 zero parameters, so the baseline is 4. The description correctly makes no mention of parameters, and there is nothing to add beyond what the empty schema already conveys.

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 'Return' with a clear resource 'identity information' and scope 'for the real host running this MCP server'. It unambiguously differentiates from sibling tools like system_summary or db_status by focusing on host identity. There is no ambiguity about what the tool does.

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 clearly implies when to use this tool – whenever an agent needs identity information about the host running the MCP server. While it doesn't explicitly name alternatives or exclusions, the purpose is so specific that an agent can infer the appropriate context without confusion.

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