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

With annotations only saying readOnlyHint=false, the description carries the side-effect burden and meets it well: invoke runs one-off without installing, install/uninstall/subscribe/cancel plus the one-off install behind invoke require owner/admin, paid/credential-required cases return links instead of failing, and publish_prompt returns a login-free shareable link. No statement contradicts the annotations; it enriches the openWorldHint with concrete external effects.

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 dense and logically ordered: catalog definition, core flow, key one-off behavior, credential/payment outcomes, install-vs-invoke guidance, action catalog, auth note, and prompt library section. Minor redundancies ('without adding the MCP to the toolkit and without bloating the tool list') and the untranslated word 'pontualmente' keep it from perfect concision.

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 23-parameter, 14-action tool with no output schema, the description covers the main workflow, return behavior for describe/invoke/publish_prompt, auth requirements, and billing edge cases. It misses the `resume` action entirely and leaves `immediate` and `tier_slug` unexplained, which are visible gaps in an otherwise comprehensive picture.

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 compensates by explaining the critical `action` enum values and tying `mcp_id`, `tool_id`, and `arguments` into the search→describe→invoke flow. It also gives meaning to the prompt-related params through the prompt library section. However, several params remain unmapped (`immediate`, `tier_slug`, `conversation`, `request_*`, `cancel_*`), so the compensation is incomplete.

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 names the resource (mcp.ai marketplace), its dual function (catalog and execution), and enumerates every major action category: search, describe, invoke, install, list_tools, subscribe/cancel, report_bug, request_mcp, and prompt-library functions. It even contrasts list_tools ('what is callable right now') and request_mcp ('build a NEW MCP') to avoid ambiguity with siblings. This is a specific, multi-verb but unambiguous purpose statement.

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?

It gives explicit decision rules: use invoke for single/occasional use, install only for permanent toolkit membership, subscribe/cancel for per-MCP billing, and request_mcp when nothing fits. It also explains the retry flow for credential and payment links returned by invoke. The only minor omission is the `resume` action, which is never mentioned.

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