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

The description discloses key behavioral traits beyond the annotations: invoke works even when the MCP is not installed, it returns a connect link for credential needs, a checkout link for empty wallets, and the one-off install behind invoke requires owner/admin. These details are not present in the annotations and are critical for the agent to anticipate side effects and user interactions.

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 and dense but front-loads the core purpose and flow. It covers a complex multi-action tool in a single paragraph without wasting words, but it could benefit from bullet points or separation of the prompt library section for improved 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?

Given the tool's complexity (23 parameters, 14 actions), the description covers the main operational flow, special cases (credential/payment links), permissions, and the additional prompt library feature. It lacks detail on some actions like 'resume' or 'list_tools', but the overall behavior and return patterns are sufficiently explained for an agent to use the tool correctly.

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 well by explaining the purpose of major parameters: action=search/describe/invoke, mcp_id, tool_id, arguments, and the prompt_* parameters for the prompt library. It does not explain every parameter (like limit, immediate, tier_slug), but the most important workflow parameters are clearly described, making the schema more interpretable.

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, functioning as both a catalog and execution platform for MCPs/tools. It uses specific verbs like 'search', 'describe', and 'invoke' to describe its core operations, and it distinguishes itself from sibling tools by being the primary access point for discovering and running MCPs.

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 an explicit core flow (action=search → describe → invoke) and directly compares alternatives: 'Use install only to make an MCP PERMANENT... prefer invoke for a single/occasional use.' It also notes that search/describe flag installation status and that write actions require workspace owner/admin, giving clear contextual guidance.

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