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

Annotations declare readOnlyHint=true and destructiveHint=false, and the description reinforces this with 'read-only' and 'never anything more invasive,' while adding a detailed method breakdown. It also warns about authorization requirements, going beyond the structured hints without contradicting them.

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?

Three sentences carry a large amount of information with no filler: the headline action, the specific scan behaviors, and the usage restriction. The description is front-loaded with the core purpose, 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 simple one-parameter read-only tool, this description covers purpose, method, restrictions, and even highlights report contents. The only gaps are domain jargon like 'lethal trifecta' being undefined and no output schema to clarify return values, but invoking the tool correctly is fully supported.

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 input schema fully documents the single url parameter, including the https:// scheme and purpose 'to scan.' The description reinforces remote-ness and entitlement but adds no new parameter-specific meaning, so the schema-coverage baseline of 3 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 opens with a specific verb and resource: 'Runs a free, read-only security scan of a remote MCP server before you connect it.' It then enumerates concrete actions (handshake, tool listing, capability ratings, prompt-injection detection, lethal-trifecta check), making the tool's function unambiguous even with no sibling tools to distinguish from.

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?

It explicitly states the trigger condition ('before you connect it') and adds a clear permission boundary ('Scan only servers you run or are entitled to connect to'). While there are no alternatives to compare against, this covers both when and under what conditions to invoke the tool.

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