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 probe mechanism (initialize and tools/list), the no-side-effect boundary ('Does not execute tools'), the output taxonomy (ALLOW/CAUTION/BLOCK), and a concrete cost ($0.01 USDC on Base). It stops short of covering timeouts, reachability requirements, or rate limits for an operation that makes outbound calls to an arbitrary URL.

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?

Purpose and trigger are front-loaded in the first clause, the capability list is packed into a single semicolon-delimited enumeration, and the cost caveat is a short trailing parenthetical. 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?

For a single-parameter tool with no output schema and no annotations, the description supplies the decision-relevant facts: what it probes, what it returns, that it does not execute tools, and what it costs. Only the target-URL expectations are underspecified.

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?

Schema description coverage is 0% and there is one parameter, serverUrl, whose meaning is only inferable from the surrounding context ('MCP server'). The description adds no format, reachability, or endpoint-shape requirements beyond the schema's bare uri format.

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 ('MCP server security audit') plus the exact trigger point ('before an agent connects or pays'), and enumerates what the audit covers (command/filesystem/wallet capabilities, injection/exfil signals, schema inputs, HSTS, tool surface). This clearly separates it from siblings like mcp_vendor_due_diligence and package_install_preflight, which target different subjects.

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 phrase 'before an agent connects or pays' gives explicit timing guidance for when to call it, which is the key decision point for a preflight tool. However, it never names an alternative or states when-not to use it (e.g., how it differs from mcp_vendor_due_diligence), leaving the sibling choice to inference.

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