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

The description discloses important behaviors: writes require workspace owner/admin, invoke works even when the MCP is not installed and runs one-off without bloating the tool list, and returns connect or checkout links when credentials/wallet are insufficient. These insights go beyond the annotations, which only indicate openWorldHint=true and no read-only/destructive hints, providing meaningful 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 long but information-dense, covering a complex tool with 14 actions. Every sentence adds value, but it is presented as one continuous block, lacking paragraph breaks or bullet points for quick scanning. This reduces structural clarity, though it is justified given the tool's scope.

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 high complexity (23 params, no output schema), the description lacks specific details on per-action return formats, required parameters for each action, and error handling. It mentions some outputs (connect link, checkout link, shareable prompt link) but does not systematically cover all actions, leaving gaps for an agent to discover.

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 must compensate. It explains the key parameters action, mcp_id, tool_id, arguments through the core flow, and details prompt-related parameters like prompt_vars and prompt_slug in the prompt library section. However, not all 23 parameters are addressed (e.g., cancel_reason, tier_slug, request_name), leaving some gap for an agent to infer.

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 it is both a catalog and a way to run MCP/tools. It distinguishes from sibling tools by focusing on discovery and execution, covering capability requests like 'find an MCP that does X' and 'is there a tool for Y', which is unique among the listed siblings.

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 provides explicit usage guidance: 'Core flow: action=search discovers MCPs by intent → describe returns one MCP's full profile... → invoke RUNS that tool.' It also contrasts invoke vs install: 'use install only to make an MCP PERMANENT... prefer invoke for a single/occasional use.' It mentions list_tools for current callable tools, and covers billing and reporting actions, giving clear when-to-use context.

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