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

Even though annotations indicate readOnlyHint=false, openWorldHint=true, and idempotentHint=false, the description adds substantial behavioral context: invoke runs an MCP one-off without installing it, returns a connect link when credentials are needed and a checkout/top-up link when payment is required, and writes require workspace owner/admin. It also reveals search/describe installed flags.

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 dense and information-rich, covering many actions and edge cases without fluff. It would benefit from clearer structural separation (e.g., bullets or sections) given its length, but every sentence earns its place by adding critical workflow or cautionary details.

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 tool with 14 actions and 23 parameters, the description covers the main execution flows, permission caveats, and exception handling (connect/checkout), making it largely sufficient for correct use. It falls slightly short on the prompt-library sub-feature's parameter details and on some niche actions like resume/tier_slug, but overall it is a robust and complete narrative.

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 role of key parameters like action (via listing enum values), mcp_id, tool_id, and query (via examples), but it does not document all 23 parameters (e.g., prompt_* fields, cancel_*, immediate, tier_slug). It provides a partial semantic map but leaves several parameters underspecified.

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 identifies the tool as the official mcp.ai marketplace catalog and execution engine, with a specific core flow (search → describe → invoke) and distinct actions (search, describe, install, invoke, list_tools, etc.). It distinguishes itself from sibling tools by being the central marketplace for both discovery and one-off execution.

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 explicit guidance on when to use invoke (one-off/occasional) vs install (permanent), explains the connect and checkout/top-up link flows with retry instructions, and clarifies when to use report_bug, request_mcp, and the prompt library functions. It also notes admin permission requirements for writes.

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