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

Beyond the annotations, the description discloses important runtime behaviors: invoke works even when the MCP is not installed, it is one-off and does not bloat the tool list, credential/background paywall flows return connect/checkout links requiring user action then retry, and writes such as install/subscribe/cancel require workspace owner/admin. It also explains installed_in_toolkit vs installed_in_workspace flags. There is no contradiction with the stated 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 dense and front-loaded with the core identity and flow. It earns most of its sentences, but it runs into one long manual-style paragraph—space use, bullets, or short separations for billing, permissions, and prompt-library would have improved scanability.

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 very complex 23-parameter, no-output-schema marketplace tool, the description is impressively complete: it explains the core lifecycle, auth/payment side effects, prompt library, and other workspaces. It still leaves gaps: it does not enumerate every parameter, anything about `resume`, the `arguments` JSON format/system, or what the exact return shapes for overview outputs will look like, so the agent may still need 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?

Schema coverage is 0%, so the description carries a strong burden here. It does add real meaning to core parameters: action values (search/describe/install/list_tools/subscribe/cancel/prompt actions), tool_id selection, prompt slug links, and cancel/billing behavior. However, several fields are left unexplained, such as limit, immediate, conversation, cancel_reason/comment, and arguments syntax; the description also refers to an 'invoke' flow that is not visible in the action enum, leaving some ambiguity.

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 opens with a strong definition: 'official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them.' It then clarifies the search–describe–invoke flow and distinguishes marketplace actions such as install, list_tools, subscribe, and the prompt library, so an agent can tell what this tool is for.

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 gives explicit decision guidance: 'prefer invoke for a single/occasional use', 'Use install only to make an MCP PERMANENT', and 'list_tools lists what is callable right now'. It also states the when-to-fallback path: 'request_mcp asks us to build a NEW MCP when nothing fits.' This is concrete when/when-not guidance.

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