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

The annotations correctly flag with readOnlyHint=false that this tool writes, which the description acknowledges. It then substantially exceeds baseline by detailing: the one-off nature of invoke (runs 'pontualmente' without adding to the toolkit), the connect link for auth requirements, the checkout/top-up link for empty wallet scenarios with a retry suggestion, and the admin/owner permission requirement for writes. Also names specific flags like installed_in_toolkit vs installed_in_workspace that the agent will see in search results.

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 dense, front-loaded, and information-dense. However, at this length a single-paragraph format is strongly felt — there are no bullets or line breaks for the prompt actions, no bold for action names, and the prose style obscures what could be skimmable distinctions (two sentences explain the pricing behavior, which is critical but buried).

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 distinct actions and zero output schema, this description is remarkably complete: it covers capability discovery, installation semantics, auth, payment, permissions, list state, the prompt library, and even edge handling for installed vs. not-installed MCPs, plus a robust single example of the billing retry loop.

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 zero schema description coverage, this dimension bears the full documentation burden, and the -described flow does not map any of the 23 parameters to actions. An agent reading this description would not know that 'limit' is the pagination control, that 'arguments' contains a JSON string to pass to invoke, or that 'message' is destructured based on the current action. The description repeatedly refers to parameters that are never explicitly enumerated (e.g., 'search_prompts finds one, get_prompt returns its full text') without explaining how those are encoded in the schema.

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 by identifying 'mcp.ai marketplace' as a catalog plus execution environment, then illustrates concrete query types ('find an MCP that does X', 'consulta um CPF'). The three-step core flow (search -> describe -> invoke) makes the tool's aggregate purpose unambiguous. Minor point off: the description covers multiple sub-capabilities (prompt library, billing) under one tool name, so the singular purpose is slightly diffused.

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 states when to use 'invoke' vs 'install': 'prefer invoke for single/occasional use' versus 'use install only to make an MCP PERMANENT'. Also names the alternative for capability discovery ('list_tools lists what is callable right now') and explicitly defines the search-then-describe-then-invoke sequence, which directly prevents misuse.

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