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

Beyond the annotations (readOnlyHint=false, openWorldHint=true), the description discloses critical behaviors: invoke runs one-off without adding to the toolkit, returns connect/checkout links when credentials or payment are needed, writes require workspace owner/admin, and the prompt library stores text prompts rather than MCPs. This complements the annotations without contradiction.

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 dense, run-on block of text without visual structure (no bullet points or sections), though every sentence is relevant. Given the tool's 14 actions and 23 parameters, the length is justifiable, but it could be better organized to improve 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?

For a highly complex tool with 14 actions, 23 parameters, and no output schema, the description covers nearly every aspect: the decision flow, auth/billing behaviors, ownership requirements, and the separate prompt library. It even describes expected outputs (connect/checkout links, full MCP profiles), making it remarkably complete.

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 carries the burden and does explain core parameters via the action flow: `action`, `query`, `mcp_id`, `tool_id`, `arguments`. However, several parameters like `immediate`, `tier_slug`, `conversation`, `report_context`, and `prompt_body` are not explained, leaving some ambiguity for those actions.

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 specific definition: 'the official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them.' It enumerates the action enum and explains its role in capability requests, installation, billing, and prompt library, clearly distinguishing it from sibling tools like connect or report_bug.

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 when-to-use guidance for key actions: 'prefer invoke for a single/occasional use' vs 'Use install only to make an MCP PERMANENT', and notes 'invoke works even when the MCP is NOT installed'. It also explains the core search→describe→invoke flow and when to use list_tools, request_mcp, and subscribe/cancel.

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