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

The annotations are sparse (only readOnly/openWorld/idempotent/destructive hints), so the description carries the behavioral burden. It adds major operational context: invoke runs tools one-off without installing, missing credentials return a connect link, empty wallet returns checkout, writes require workspace owner/admin, and prompt links open without login. These details meaningfully go beyond the structured annotations, and no contradiction is present.

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 the tool is a multi-action dispatcher with 14 actions, so the length is largely justified. It is front-loaded with the core flow, then covers install-vs-invoke, billing/auth behavior, and the prompt library. It is dense rather than repetitive; minor run-on structure costs it a perfect score.

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 high complexity (14 actions, 23 parameters, no output schema), the description is unusually complete: it explains the full search → describe → invoke flow, auth/billing side effects, install semantics, permissions, and prompt publishing. The main gaps are exact return shapes, error/retry workflows beyond the connect/checkout links, and exhaustive parameter mapping, but the description still provides enough context for safe invocation.

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% across 23 parameters, so the description must compensate. It does explain the core action flow and clarifies tool_id, arguments, prompt_vars, and prompt_slug indirectly, but many parameters are left undocumented: limit, query, immediate, conversation, prompt_targets, prompt_tool, request_details, cancel_reason, and cancel_comment. The description is helpful but only partially compensates for the complete lack of schema-level parameter descriptions.

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 marketplace as the official mcp.ai catalog and execution layer, with an explicit core flow: search discovers MCPs, describe returns profiles, invoke runs tools, install makes them permanent. This goes well beyond a vague verb+resource statement and effectively differentiates the marketplace's role from sibling tools like report_bug or toolkit_info.

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 direct usage guidance: 'prefer invoke for a single/occasional use' and 'Use install only to make an MCP PERMANENT.' It also maps each action to its purpose: search/describe, invoke, install, list_tools, subscribe/cancel, report_bug, request_mcp, and the prompt library actions. This is explicit when-to-use guidance with clear alternatives.

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