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

Beyond annotations, the description reveals onboarding behavior: 'invoke works even when the MCP is NOT installed', auth/payment flows ('returns a connect link', 'returns a checkout/top-up link'), and permission constraints ('require workspace owner/admin'). This is significant behavioral 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 densely structured with a core flow and explicit exceptions. Every sentence adds unique information, and the use of colons and arrows makes it scannable despite its length.

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 no output schema and 14 actions, the description covers the main flows, auth/payment edge cases, permissions, and the prompt library. It omits some return-format details but provides enough context for an agent to select and invoke actions correctly.

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 explains the 'action' enum and the key fields like 'tool_id' and 'arguments' via the flow, and mentions prompt-related variables indirectly. However, many of the 23 parameters (e.g., 'immediate', 'tier_slug', 'conversation') are left unexplained, so it only partially compensates.

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 catalogs and runs MCPs, covering 'capability requests'. It distinguishes from siblings by explicitly stating it covers the catalog and prompt library, which other tools like 'authenticate' and 'connect' don't.

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?

Explicit guidance is given: 'Use install only to make an MCP PERMANENT... prefer invoke for a single/occasional use.' It also explains the core search→describe→invoke flow and contrasts list_tools as 'what is callable right now.'

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