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

Discloses key behavioral traits beyond annotations: invoke works on uninstalled MCPs without adding them to the toolkit, returns connect links for missing credentials, checkout links for empty wallets, and retry logic. Also clarifies that install makes MCPs permanent and that writes need workspace owner/admin. No contradiction with 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 long but every sentence adds distinct value: it opens with a clear scope statement, then efficiently covers the flow, key distinctions, permissions, and edge cases. No filler or repetition; the density is justified by the tool's 14 actions and 23 parameters.

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 high complexity and no output schema, the description covers the main flows, permissions, auth/payment edge cases, and the prompt library. It does not specify return formats for every action, but it gives enough behavioral context (e.g., invoke returns connect/checkout links, get_prompt returns text with variables filled) to be useful.

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?

The schema provides zero descriptions (0% coverage), so the text must compensate. It explains the meaning of action values (search, describe, invoke, install, etc.), tool_id (selected tool), arguments (passed to invoke), and prompt_slug/prompt_vars. Not every parameter is documented (e.g., limit, immediate, tier_slug), but the core parameters are given useful context.

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 marketplace for discovering and running MCPs, covering both catalog search and execution. It distinguishes itself from siblings by describing the full lifecycle (search, describe, install, invoke, subscribe) that other tools like toolkit_info or connect do not cover.

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?

Provides explicit when-to-use guidance: 'prefer invoke for a single/occasional use' vs 'Use install only to make an MCP PERMANENT'. It also explains the decision flow (search → describe → invoke) and separates the prompt library actions, plus notes that writes require workspace owner/admin.

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