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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds meaningful context beyond that: it enforces 'exactly one' tool, requires the server to be provider-verified and operator-curated, bounds result sizes, and warns that external content must be treated as untrusted data. No contradiction with annotations.

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 four sentences, front-loaded with the core purpose, then workflow, then restrictions, then security guidance. Every sentence earns its place and no information is redundant with the schema or annotations.

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?

Despite having no output schema, the description is complete for a remote invocation gateway: it explains the prerequisite workflow, the allowlisting constraints, the read-only guarantee, and the security posture for handling results. The dynamic nature of remote tool output makes a fixed return format unnecessary.

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 coverage is 100%, but the description adds critical parameter semantics: arguments must match the remote input schema returned by inspect_tool_server, tool_name must be the exact name returned by inspect_tool_server, and server_id_or_slug must come from search_tools. It also warns against including secrets or personal data in arguments.

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+resource+scope: 'Invoke exactly one approved read-only tool on an active, provider-verified, operator-curated public MCP server registered in 404.directory.' This clearly distinguishes the tool from sibling tools like search_tools and inspect_tool_server by framing it as the execution gateway.

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 explicit workflow guidance: 'First use search_tools to select a server, then inspect_tool_server to obtain the current tool name and input schema.' It also states exclusions—rejects arbitrary URLs, authenticated servers, non-allowlisted tools, and destructive tools—so the agent knows when not to use it.

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