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

Beyond the annotations, the description richly discloses behavioral traits: invoke runs tools one-off without installing or bloating the tool list, auth and payment failures return actionable links, and writes require workspace owner/admin. It also contrasts search/describe flags for installed state and explains that prompt links open without login. No contradiction with the annotations; the description adds substantial context they do not provide.

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 unusually dense and well organized: core flow first, then the invoke nuance, install vs invoke, permissions, and prompt library. Almost every sentence earns its place. Minor points like the localized example 'consulta um CPF' and the awkward 'pontualmente' add slight noise, but they do not undermine overall structure.

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 the tool's complexity (14 actions, 23 params, no output schema), the description covers most key behaviors: discovery, invocation, installation, billing/subscription, permissions, and prompt-library operations. It leaves some output expectations unstated for actions like report_bug, request_mcp, subscribe, and cancel, but for an agent selecting and invoking the tool, the critical paths are sufficiently 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 23 parameters and 0% schema description coverage, the description carries a heavy burden and does add meaning for many action values and prompt-related parameters (e.g., action=invoke, prompt_vars filling, publish_prompt returning a slug link). However, several non-obvious parameters remain unexplained, such as limit, query, immediate, tier_slug, and conversation, so an agent still has to guess or infer their formats and relevance.

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 and runtime, with a specific verb+resource framing ('catalog of every MCP/tool, AND the way to run them'). It also lays out the core search→describe→invoke flow, making the main purpose unambiguous. It does not explicitly compare itself to sibling tools like authenticate or connect, and the added prompt-library scope makes it multi-purpose, so it falls just short of a perfect 5.

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 the major actions: 'prefer invoke for a single/occasional use', 'Use install only to make an MCP PERMANENT', 'list_tools lists what is callable right now', and 'request_mcp asks us to build a NEW MCP when nothing fits'. It also explains the auth/billing edge cases (connect link, checkout link) and when to retry. This is model behavior for guiding tool selection.

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