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

The description goes far beyond the annotations by explaining the one-off behavior of invoke (works when MCP is not installed, returns connect/checkout links), the admin requirement for writes, and the distinction between toolkit/workspace installation. These are critical behavioral nuances not present in the structured metadata.

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 well-structured, with a clear opening, a core-flow section, a KEY note, and separate prompt-library coverage. It front-loads the most important information and avoids redundancy, though some sentences could be tightened to reduce overall verbosity.

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 complex tool with 23 parameters and no output schema, the description covers the primary workflows, conditional behaviors (credentials/payment), and permission constraints impressively well. It omits details on some secondary actions (e.g., resume, uninstall nuances) and does not explain every parameter, but the core usage is sufficiently specified.

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 zero schema_description_coverage, the description must compensate. It thoroughly explains the 'action' parameter by enumerating each action's purpose, and contextualizes tool_id, mcp_id, and prompt fields. However, many parameters (limit, immediate, conversation, tier_slug, cancel_reason, etc.) remain unexplained, leaving meaningful ambiguity despite the detailed narrative.

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 opening sentence clearly defines the tool as 'the official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them.' It then details the core flow (search → describe → invoke) and lists all sub-actions, making the purpose unmistakable and distinguishing 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 advises when to use invoke vs install ('prefer invoke for a single/occasional use' and 'Use install only to make an MCP PERMANENT'), and distinguishes list_tools, subscribe/cancel, request_mcp, and the prompt library actions. It also notes that writes require owner/admin, which further guides appropriate use.

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