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

The description discloses critical behavioral details beyond annotations: writes (install/uninstall/subscribe/cancel and the one-off install behind invoke) require workspace owner/admin; invoke runs tools one-off without installing or bloating the toolkit; credential/payment issues return connect/checkout links. This is rich, non-obvious context.

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 long but every sentence earns its place. It uses a clear narrative flow with arrows and semicolons to pack dense information, and the length is justified by the tool's 14 actions and 23 parameters. There is no fluff or repetition.

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 tool with 23 optional parameters, 14 actions, and no output schema, the description is remarkably thorough: it covers the core flows, one-off invocation behavior, permanent installation trade-offs, billing/auth failure modes, and the separate prompt library. Minor gaps include missing explanations for 'resume', 'immediate', and cancel_reason enums, leaving some edge cases to infer.

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 roles of key parameters (action, mcp_id, tool_id, arguments, prompt fields) through the workflow narrative. However, it leaves many parameters (immediate, tier_slug, resume, cancel_reason, prompt_targets) undocumented, which is a notable gap for such a complex tool.

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, serving as both the catalog of MCPs/tools and the way to run them. It enumerates distinct actions (search, describe, invoke, install, subscribe, etc.) and distinguishes itself from siblings by also covering 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 provides a explicit core workflow (action=search → describe → invoke), contrasts invoke vs install ('prefer invoke for a single/occasional use'), and clarifies when to use list_tools, subscribe/cancel, report_bug, request_mcp, and prompt library functions. It also covers billing/auth edge cases with instructions to retry after the user acts.

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