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

Annotations already signal readOnlyHint=false, openWorldHint=true, etc., but the description adds critical context: invoke works even when the MCP is not installed, returns a connect link if credentials are needed, returns a checkout/top-up link if payment is required, and writes require workspace owner/admin. It also notes that search/describe flag installed_in_toolkit vs installed_in_workspace, all beyond the boolean 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 description is a single dense paragraph that covers many topics, making it hard to scan quickly. It repeats 'MCP' frequently and packs multiple clauses with 'and' and '→'. Every sentence carries information, but a bulleted or sectioned layout would significantly improve readability and agent parsing.

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 (14 actions, 23 params, no output schema), the description covers the core search→describe→invoke flow, install vs invoke, auth/payment outcomes, admin requirements, and the prompt library. It stops short of specifying return shapes for every action (e.g., search results, list_tools format) or handling error cases, but it covers the primary usage patterns well.

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 compensates by explaining the action enum values and the meaning of key parameters (query, mcp_id, tool_id, arguments, immediate). It also covers the prompt library parameters (search_prompts, get_prompt, publish_prompt, prompt_vars, etc.). However, some parameters (limit, cancel_reason, report_context, request_details) are only implicit via action names, so a slightly higher explicitness would be ideal.

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 with a clear, specific statement: 'The official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them.' It enumerates distinct actions (search, describe, invoke, install, list_tools, prompt operations) and explicitly covers the scope (MCPs and prompt library), which distinguishes it from sibling tools like authenticate or connect.

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 explicitly lays out the core flow: 'action=search discovers MCPs by intent → describe returns one MCP's full profile ... → invoke RUNS that tool.' It also provides explicit contrast: 'prefer invoke for a single/occasional use' versus 'Use install only to make an MCP PERMANENT.' It names when to use request_mcp, list_tools, and the prompt library actions, plus states the admin requirement for writes.

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