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

The description goes well beyond the annotations. It discloses that invoke works even when the MCP is not installed, runs one-off without bloating the tool list, returns connect/checkout links for missing credentials/payment, and requires workspace owner/admin for writes. It also explains the installed_in_toolkit vs installed_in_workspace distinction. This is rich behavioral context that annotations do not provide.

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 with no fluff—every sentence adds value explaining the dual catalog/execution role, edge cases, and auth. It is a single paragraph, which makes it harder to scan, but the size is justified given the tool's complexity (14 actions, 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 this complex with no output schema, the description covers the main flow, auth requirements, payment/credential edge cases, and the prompt library feature. Missing details on some niche parameters, but overall it gives an agent a strong, actionable mental model.

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?

Schema description coverage is 0%, so the description must compensate. It does explain the central parameters: action (via the enumerated actions and core flow), mcp_id, tool_id, and arguments. However, many parameters like limit, immediate, tier_slug, prompt_title, prompt_category, and prompt_targets are not explicitly described, leaving the agent to infer from names. It partially compensates but not fully for 23 parameters.

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 then details the core search/describe/invoke flow and distinguishes from sibling tools by naming report_bug, request_mcp, and prompt-related actions. This gives the tool a definite scope and role.

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 says when to use invoke vs install: 'Use install only to make an MCP PERMANENT in the active toolkit...; prefer invoke for a single/occasional use.' It also outlines when to use search, describe, invoke, and the prompt library functions. This is exemplary 'when-to vs alternatives' guidance.

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