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

Beyond the annotations, the description discloses substantial behavioral context: writes require workspace owner/admin, invoke runs one-off without bloating the toolkit, missing credentials return a connect link, unpaid usage returns a checkout/top-up link, and prompt share links open without login. These details go well beyond the generic readOnlyHint/openWorldHint annotations and present no contradiction.

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 and dense, but nearly every clause adds real behavioral or routing value, and it front-loads the core purpose and flow. It is structured as one run-on block, which hurts scanability, but given the tool's 14-action surface, the length is justified.

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 breadth and the absence of an output schema, the description covers discovery, invocation, installation, billing, bug reporting, MCP requests, and the prompt library. It explains connect/checkout retry flows and permission requirements, though it does not detail return shapes, error cases, or how this tool relates to sibling tools like authenticate/connect. This is strong but not exhaustive.

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 and 23 parameters, the description carries the parameter-semantics burden but only partially handles it. It explains the action enum values and names key identifiers like tool_id and mcp_id, but most parameters—arguments, immediate, tier_slug, prompt_body, report_context, request_details, etc.—are not individually explained. The agent gets strong action-level semantics but weak parameter-level detail.

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 — the in-platform catalog of every MCP/tool, AND the way to run them.' It names the core search → describe → invoke flow and distinguishes marketplace from sibling tools by covering discovery, execution, installation, billing, and prompt-library actions. This is a specific, resource-anchored purpose statement with strong sibling differentiation.

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' vs. 'Use install only to make an MCP PERMANENT,' and defines list_tools as 'what is callable right now.' It also explains when to retry after a connect/checkout link and when to use request_mcp ('asks us to build a NEW MCP when nothing fits'). This is clear when-to-use versus when-not-to-use guidance.

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