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

Goes well beyond the minimal annotations: explains the one-off nature of invoke (no toolkit bloat), the connect link for missing credentials, checkout/top-up link for empty wallet, admin requirement for writes, and the distinction between MCP catalog and prompt library. No contradictions with 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 long, but it is highly structured (introduction, core flow with arrows, KEY callout, prompt library section). The density is justified given the platform contains 14 actions; still, it could be trimmed (e.g., the 'consulta um CPF' example) and the mixed-language word 'pontualmente' slightly hurts clarity.

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 umbrella tool with 23 parameters, no output schema, and 14 actions, the description covers the full lifecycle: discovery, describe, invoke, install, billing, permission requirements, prompt library, and how to request new MCPs. It equips an agent to choose and run the correct action in most scenarios.

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 teaches the central action parameter by explaining what each action does (search, describe, invoke, install, list_tools, subscribe, cancel, report_bug, request_mcp, prompt actions). It also explains the relationship between mcp_id, tool_id, and arguments through the core flow. However, many of the 23 parameters (e.g., immediate, tier_slug, conversation, prompt_vars format) are not individually described, leaving some gaps.

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 'The official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them,' clearly defining the verb (catalog/run) and resource (MCP/tool). It covers the full action set, distinguishing it from sibling tools like toolkit_info or report_bug by describing itself as the central discovery and invocation hub.

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?

Explicitly lays out the core flow (search → describe → invoke), contrasts invoke vs install ('prefer invoke for a single/occasional use'), notes list_tools for callable tools, request_mcp for new MCPs, and specifies when billing/subscribe/cancel apply. This gives the agent clear selection logic.

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