tunnel_list

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

With no annotations, the description must convey behavioral traits. It mentions a 'live health probe' and describes output fields (tunnel_id, connections, pins), indicating it's a read-only operation. No side effects are suggested, but it could be more explicit about idempotency or rate 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?

Two sentences, no waste. The main action is front-loaded, and additional context about related tools and fields is provided efficiently.

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 parameterless list tool with no output schema, the description sufficiently covers what it does and what the output contains. It references sibling tools to fill context, making it complete for the agent to select and invoke correctly.

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 schema description coverage is 100%. Baseline for 0 params is 4, and the description does not need to add parameter details. It adds value by explaining what the output contains.

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 clearly states 'List the tunnels currently open in THIS MCP instance' with a specific verb and resource. It distinguishes from sibling tools by mentioning connection_list for configured-but-not-open tunnels, and clarifies how fields relate to other tools like down_tunnel and up_tunnel.

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?

Provides explicit guidance on when to use this tool (to see open tunnels) and points to connection_list as an alternative for configured-but-not-open tunnels. It also explains the meaning of 'connections' and 'pins' in relation to other tools, helping the agent choose correctly.

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