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

The description goes far beyond the minimal annotations (readOnlyHint=false, etc.) by detailing side effects: invoke runs even if the MCP is not installed and does not add it to the toolkit, install makes it permanent, writes require owner/admin, and payment/auth flows involve connect/checkout links that require retry. There is no contradiction with annotations—the write capability is appropriately described.

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 without bullet points or logical breaks, making it hard to scan. While every sentence adds value, the lack of structure reduces readability. It could be improved by grouping related actions (e.g., marketplace operations vs. prompt library) into separate sections.

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 tool's complexity (23 parameters, no output schema, multiple sub-actions), the description is remarkably comprehensive. It covers the full action set, expected returns (e.g., describe returns profile with tools/pricing/auth, invoke returns connect/top-up links), permission requirements, and the prompt library—all in one coherent narrative. No significant context is missing.

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 carries the burden of explaining parameters. It effectively covers core parameters like action, mcp_id, tool_id, arguments, and the prompt_* fields, linking them to the narrative flow. However, some parameters (limit, immediate, tier_slug, cancel_comment) are left unexplained, leaving minor gaps despite the overall strong contextual mapping.

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 clearly defines the tool as the official mcp.ai marketplace, detailing its role as a catalog and execution engine for MCPs and prompts. It names specific verbs (search, describe, invoke, install) and the resource (MCPs/prompts), and it distinguishes itself from siblings by being the central hub that handles discovery and execution.

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 provides explicit usage guidance, including the core flow (search→describe→invoke), when to prefer invoke over install ('prefer invoke for a single/occasional use; use install only to make an MCP PERMANENT'), and when to use other actions like list_tools, subscribe, and report_bug. It also clarifies write permission requirements (owner/admin) and behavior when credentials or wallet are missing.

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