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

Exceeds annotation coverage by explaining behavioral traits: invoke runs even when the MCP is not installed, returns connect/checkout links for auth/payment, install makes tools permanent, and writes require workspace owner/admin. Also clarifies search/describe flag installed status. This adds substantial context beyond the annotations (which only indicate non-read-only, open-world, non-idempotent, non-destructive).

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 every sentence carries valuable info, covering core flow, invoke behavior, auth/billing handling, install vs invoke, permissions, and the prompt library. It is structured as a continuous paragraph without bullet points, but the content is dense and appropriately sized for the tool's complexity.

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 23 parameters and no output schema, the description provides a thorough overview of the marketplace's capabilities, core flow, pricing/auth interactions, permission requirements, and the prompt library. It explains how invoke handles missing credentials and empty wallets, and how install differs. This is complete enough for an agent to select and invoke the tool effectively.

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 description coverage is 0%, so the description must compensate. It explains the action enum values (search, describe, install, invoke, etc.) and relevant parameters (tool_id, arguments, prompt_slug) within the narrative. However, it does not systematically describe many parameters (limit, query, message, immediate, tier_slug, etc.), leaving gaps for an agent needing precise parameter semantics. It partially compensates but not fully.

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, serving as the catalog of every MCP/tool and the way to run them. It details the core flow (search, describe, invoke) and distinguishes it from siblings by focusing on discovery and one-off execution. The verb+resource+scope is specific and unmistakable.

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?

Provides explicit guidance on when to use invoke vs install ('prefer invoke for a single/occasional use', 'Use install only to make an MCP PERMANENT'), when to use search vs describe, and when to use request_mcp. It also mentions permission requirements for writes and explains how to handle auth/billing links, giving clear context and alternatives.

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