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

Annotations already cover the safety profile (readOnly, non-destructive, open world), and the description adds substantial context beyond them: no tool is invoked during the scan, definitions are only read up to a size limit, truncation is reported, results come back as a letter grade plus findings, and access is throttled per IP. These are exactly the operational traits an agent needs before invoking.

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 front-loaded with the value proposition and the core action, then closes with two short constraints. The phrase 'and more' is mildly vague and the middle sentence runs long, but no sentence is 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?

With no output schema, the description still explains the return value (grade A to F with findings), discloses the truncation case, and covers cost and rate constraints. An agent has everything needed to decide to call it and interpret the result.

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?

There is one parameter at 100% schema coverage, so the schema already documents the URL and its format. The description implies the target is a remote MCP server but adds no syntax, host constraints, or failure semantics beyond what the schema states. Baseline 3 is appropriate when the schema does the heavy lifting.

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?

Names a specific verb and resource (scan a remote MCP server) and enumerates the concrete work performed: connecting via Streamable HTTP, reading tool definitions and instructions, and checking for tool poisoning classes such as hidden instructions, invisible characters, and credential-file requests. This is clearly distinct from the sibling service-directory tools (get_service, list_categories, search_services).

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 gives implicit usage context: it is free, it is non-invasive ('without calling any tool'), and it is rate limited 'per IP'. However, it never states when an agent should choose this over a sibling such as preflight_check, nor does it list exclusions or prerequisites. Usage is inferable but not explicit.

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