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

Beyond the annotations (readOnlyHint=false, openWorldHint=true, etc.), the description discloses key behavioral details: invoke works even when the MCP is not installed (one-off run without adding to toolkit), returns connect/checkout links for missing credentials or payment, and search/describe flag installed status. It also mentions that writes require owner/admin, adding valuable context not covered by 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 dense and front-loaded with purpose, but it is a large wall of text covering many actions and the prompt library. Every sentence adds value, yet a structured format (e.g., bullets) could improve readability. It is appropriately sized for the tool's complexity but slightly verbose.

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 high complexity (14 actions, 23 params, no output schema), the description is remarkably complete. It explains the core flow, edge cases like connect/checkout links, auth requirements, and the prompt library's search/get/publish lifecycle. It also covers what each main action returns, compensating for the lack of an output schema.

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%, so the description carries the burden of explaining parameters. It explains the core 'action' enum and several key parameters (e.g., tool_id, mcp_id, prompt-related fields) through workflow examples, but does not explicitly describe every one of the 23 parameters (e.g., limit, immediate, tier_slug). The high-level guidance compensates substantially, but a few parameters remain under-documented.

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 states the tool is the official mcp.ai marketplace, acting as both a catalog of every MCP/tool and the way to run them. It differentiates itself from siblings by focusing on discovery, description, invocation, and management of MCPs, with a clear primary verb+resource structure. It also distinguishes between MCP-related actions and the prompt library.

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 when-to-use guidance: prefer invoke for occasional use, use install only to make an MCP permanent, and lists actions like search, describe, list_tools, subscribe/cancel, report_bug, and request_mcp with their intended purposes. It also clarifies that writes require workspace owner/admin, providing clear exclusions and operational context.

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