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

Despite annotations being minimal (readOnlyHint false, openWorldHint true), the description discloses important behaviors: invoke runs tools without installing them, writes require workspace owner/admin, credential gaps produce connect links, and payment gaps produce checkout links. This goes well beyond the annotations and provides critical operational context.

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 but well-organized with a core-flow breakdown, a KEY callout, and a separate prompt-library section. It is long, but the tool is a multi-action dispatcher with 14 actions, so the length is largely justified. Minor formatting improvements could help scannability.

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?

The description covers the main workflow, auth requirements, billing behavior, install-vs-invoke semantics, and the prompt library. It does not mention the 'resume' action or some action-specific parameters, and there is no output schema to clarify return shapes, leaving minor gaps for a tool this complex.

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 carries the burden. It explains the action enum values and the roles of key parameters like tool_id, mcp_id, prompt_vars, and prompt_slug. However, with 23 parameters, several remain unexplained (limit, query, immediate, tier_slug, conversation, cancel_reason, etc.), though many are inferable from names.

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 explains its dual role: discovering/describing MCPs and running them. It names the core flow (search → describe → invoke) and distinguishes itself from sibling tools by covering marketplace-specific actions like install, subscribe, and prompt-library operations.

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: prefer invoke for one-off use, use install only for permanent toolkit additions, use list_tools for currently callable tools, and use request_mcp when nothing fits. It also explains when invoke returns connect/checkout links and how to proceed, which is actionable routing guidance.

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