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

Even with useful annotations, the description adds substantial behavior: invoke runs tools one-off without bloating the toolkit, writes require workspace owner/admin, credential and payment gaps surface as connect/checkout links, install makes MCPs permanent, and prompt publish links open without login. This goes far beyond the basic read/write hints in the 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 text is long but appropriately dense for a tool with 14 actions and 23 parameters. It front-loads the core search→describe→invoke flow before addressing install, permissions, billing, and the prompt library. Minor issues include a run-on opening and the out-of-place Portuguese word "pontualmente", but most sentences earn their place.

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 multi-action hub, the description is remarkably complete: it covers discovery, one-off execution, installation, billing, permissions, bug reports, MCP requests, and prompt library operations. It does not fully describe return payloads for search/list_tools/invoke success, but it does explain key result links and flags. A few actions like resume and the immediate parameter remain underspecified.

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 carry the parameter-meaning burden. It does meaningfully explain the core action parameters (action, mcp_id, tool_id, arguments), billing actions, and prompt parameters like prompt_vars and prompt_slug. However, some parameters such as immediate, resume, tier_slug, and conversation receive no explanation, leaving gaps for a 23-parameter tool.

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 what the tool is: "the official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them." It then enumerates a concrete core flow (search → describe → invoke) and distinct action families (install, subscribe, prompts), making the tool's broad purpose explicit and distinguishable from simple sibling tools like authenticate or show_version.

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 routing guidance: "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 when invoke returns connect/checkout links and to retry afterward, giving the agent clear decision rules.

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