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

With no annotations, the description carries the full burden and does well: it discloses the live network connection, the exact handshake performed (initialize and tools/list), that no credentials are sent, and a 10 s timeout. It doesn't discuss failure modes (unreachable URL, non-MCP endpoint) or possible side effects of probing arbitrary URLs, which keeps it short of a 5.

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 with zero filler; the action, its mechanics, its limits and the routing advice are all front-loaded and every clause earns its place.

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 one-parameter probe with no output schema, the description tells the agent what is returned (status, protocol, tools, estimated token cost) and the operational constraints. Nothing needed to invoke it correctly 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?

Only one parameter (url) and schema coverage is 100%, with the schema itself documenting it as an HTTPS MCP endpoint URL. The description adds no syntax detail beyond the schema, so the baseline of 4 for a fully documented single parameter applies.

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+resource: connects to an MCP server URL now and reports status, protocol, tools and token cost. It also explicitly contrasts itself with the sibling lookup_server, so an agent can route between the two without opening either schema.

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?

Gives an explicit when-to-use rule: 'For registry servers prefer lookup_server, which has exact counts.' That names the alternative and the condition that selects it, leaving nothing to inference.

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