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

It discloses important non-obvious behaviors beyond annotations: invoking an uninstalled MCP runs it one-off without adding it to the toolkit, installs make tools natively available in future sessions, and install/uninstall/subscribe/cancel require workspace owner/admin. It also covers paid wall and authentication/connect checkouts, which are critical operational details.

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, covering identity, core flow, invoke vs installation, permissions, payments, and prompt-library functionality. It is a long single block and could benefit from bullets or section breaks, but each sentence contributes distinct decision-relevant information, so little is wasted.

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 complex tool with 23 parameters, no output schema, and many behavioral variations, the description is unusually complete: it explains the search flow, return links for payment/auth, permit requirements, installed vs. uninstalled behavior, and the prompt library. It still lacks explicit output expectations for some enumerated actions like resume, and a few parameters are left 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%, so the description carries the semantic burden. It explains the main action parameters (action, query, mcp_id, tool_id, arguments, prompt_*, cancel_*) and how they fit into the workflow. Some parameters remain unexplained, though, such as limit, immediate, conversation, request_name, and resume, so the coverage is strong but not complete for a 23-parameter dispatcher.

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 by defining the tool as "the official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them," which is specific and clearly distinguishes it as the marketplace/runtime owner. It also lays out the core flow: search discovers, describe returns details, invoke runs, and install makes permanent.

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 a single/occasional use," "Use install only to make an MCP PERMANENT," and "list_tools lists what is callable right now." It also explains the retry flow when credentials or payment are needed, which is exactly the kind of decision support an agent needs.

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