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

The annotations only provide readOnlyHint=false and openWorldHint=true, so the description carries the behavioral burden. It adds important context: invoke runs uninstalled MCPs without bloating the toolkit, missing credentials return a connect link, empty wallets return a checkout link, writes require workspace owner/admin, and prompt links open without login. No contradiction with 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 a single dense paragraph, but nearly every sentence contributes operational knowledge. It could benefit from structure or bullets given the scope, but it avoids fluff and front-loads the primary purpose in the first sentence.

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 this broad, the description is remarkably complete: it covers discovery, one-off invocation, permanent installation, permissions, billing, connect/checkout flows, prompt library, and bug reporting. Minor gaps remain, such as no explanation of the 'resume' action and no mention of return shapes, but no output schema exists to offload that burden.

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?

The description thoroughly explains the central action enum and its workflow, including search, describe, invoke, install, list_tools, subscribe/cancel, and the prompt-related actions. However, with 23 parameters and 0% schema description coverage, most fields like limit, immediate, tier_slug, cancel_reason, prompt_targets, and request_details receive no explanation beyond their names.

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, covering both catalog discovery and execution of MCPs. It articulates a specific core flow (search → describe → invoke) and differentiates its role from the provided sibling tools.

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?

It gives explicit action-level guidance: prefer invoke for one-off use, use install only to make an MCP permanent, use subscribe/cancel for billing, and use request_mcp when nothing fits. It does not explicitly contrast against sibling tools like authenticate/connect, but it does explain when connect links are returned.

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