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

Beyond the thin annotations (readOnlyHint=false, openWorldHint=true), the description discloses critical behaviors: invoke runs tools one-off even when uninstalled, credential/login flows return connect links, empty wallets return checkout links, and writes require workspace owner/admin. It also reveals installed_in_toolkit vs installed_in_workspace flags that search/describe report.

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 and the core flow, and every sentence adds substantive value. It is, however, a long single block mixing the MCP marketplace and prompt-library subsystems, so a bulleted or sectioned structure would improve scannability.

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 14 actions, 23 parameters, and no output schema, this description covers the central flows—discovery, one-off invocation, installation, billing, troubleshooting, and prompts—thoroughly. It omits details on some actions like resume, immediate, and the full cancel workflow, but the core use cases are well supported.

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 at the action level by explaining the action enum values and the tool_id selection flow, plus mention of prompt variables. However, most of the 23 parameters (e.g., immediate, tier_slug, request_details, prompt_targets, cancel_reason) remain undefined, so the agent still lacks precise semantics for many fields.

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 it is 'the official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them.' It outlines a specific core flow (search → describe → invoke) and enumerates the major action groups, distinguishing it from sibling tools like authenticate, toolkit_info, and show_version.

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 explicitly contrasts 'Use install only to make an MCP PERMANENT in the active toolkit... prefer invoke for a single/occasional use.' It also explains when to use search, describe, invoke, list_tools, subscribe/cancel, report_bug, request_mcp, and the prompt-library actions, giving clear selection guidance.

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