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

The description goes well beyond the annotations by explaining the key side effects and conditions: invoke runs a tool one-off without adding it to the toolkit, may return a connect link or checkout link, install makes an MCP permanent, and writes require owner/admin. It also notes that search/describe flag installed status. This discloses critical behavior not evident from the sparse annotations, and it does not contradict the 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 long but information-dense, covering multiple sub-tools and workflows in a single paragraph. It is front-loaded with the main purpose and uses explicit markers like 'KEY:' to highlight critical behaviors. While it could be broken into sections for readability, every sentence contributes meaningful content without significant redundancy.

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 complexity (23 parameters, 14 actions, no output schema, weak annotations), the description provides a strong overview of behavior, permissions, payment/auth handling, and the prompt library. However, it omits certain actions like 'resume' and does not explain all parameters, leaving minor gaps. Overall, it is sufficient for an agent to select and invoke the tool correctly in most scenarios.

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 must compensate. It explains the action enum in detail (search, describe, install, invoke, etc.) and implicitly defines mcp_id, tool_id, and arguments through the core workflow. However, many other parameters (limit, query, message, immediate, tier_slug, prompt_*, conversation, etc.) are not described, leaving their semantics unclear. The description adds value for the central parameters but not for the full parameter surface.

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 identifies the tool as the official mcp.ai marketplace, a catalog of MCP/tools and a way to run them. It distinguishes its scope by enumerating the core flow (search → describe → invoke) and its role as a meta-tool for both discovering and executing MCPs, while also covering the separate prompt library. This is a specific, resource-focused statement that differentiates it from 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?

The description explicitly explains when to use invoke versus install: 'prefer invoke for a single/occasional use' and 'Use install only to make an MCP PERMANENT'. It also outlines the auth/payment flows (connect link, checkout link) and clarifies that writes require workspace owner/admin. It further distinguishes the prompt library (search_prompts, get_prompt, publish_prompt) from MCP actions, providing clear usage guidance within the tool.

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