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

Goes well beyond the generic annotations by revealing concrete behaviors: invoke works even when the MCP is not installed, returns connect/checkout links, writes require workspace owner/admin, and install makes MCP permanent in the toolkit. This adds context about side effects and permission requirements.

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 a single dense paragraph with many run-on sentences. Despite covering complex functionality, it lacks bullet points or clear sections, making it harder to parse. It is long but every sentence adds information, so it earns a middle score.

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?

Given the complexity (23 params, no output schema), the description covers the core flow, permissions, auth/checkout behaviors, and the prompt library subsystem well. It doesn't detail every action or return format, but provides enough for correct tool selection and invocation.

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?

With 0% schema description coverage, the description compensates by explaining the action enum values (search, describe, invoke, install, list_tools, etc.) and core parameters like mcp_id/tool_id/arguments via the flow. However, several parameters (tier_slug, request_name, cancel_reason, prompt_category, etc.) remain undocumented, preventing a perfect score.

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 'The official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them,' which clearly identifies the resource and its dual role. It then enumerates the core action flow (search → describe → invoke), distinguishing this tool from siblings like authenticate or report_bug.

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?

Provides explicit when-to-use guidance: 'prefer invoke for a single/occasional use', 'Use install only to make an MCP PERMANENT', and maps sibling-like functions: 'list_tools lists what is callable right now', 'subscribe/cancel handle per-MCP billing; report_bug sends feedback; request_mcp asks us to build a NEW MCP when nothing fits.'

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