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

Annotations only provide generic hints (readOnlyHint=false, idempotentHint=false, destructiveHint=false). The description adds significant context: 'invoke works even when the MCP is NOT installed — it runs the tool pontualmente (one-off)', 'If the MCP needs a credential/login, invoke returns a connect link', and 'Writes... require workspace owner/admin.' This goes well beyond the 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 logically structured: what it is, core search/describe/invoke flow, the KEY invoke distinction, install vs invoke, other actions, prompt library, and permissions. Every sentence contributes useful information without padding.

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 23 params, 14 enum actions, and no output schema, the description covers the major flows, permissions, and behavioral nuances but omits the 'resume' action and several params (immediate, tier_slug, cancel_reason, prompt_targets, etc.). It is comprehensive for core usage but not exhaustive.

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 23 params and 0% schema description coverage, the description carries the burden. It adds meaning to key parameters: action (search/describe/invoke/install...), mcp_id, tool_id, arguments, and prompt_slug/vars through the explained flows. However, many params (limit, query, immediate, tier_slug, cancel_reason, etc.) are not covered, so it does not fully compensate.

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 'The official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them,' clearly defining the tool's purpose. It further explains the core search/describe/invoke flow and the prompt library, distinguishing this tool from siblings like authenticate and report_bug.

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 in the active toolkit... prefer invoke for a single/occasional use.' The description also outlines when to use search vs describe vs invoke, and mentions subscribe/cancel, report_bug, request_mcp, and list_tools, providing clear when-to-use direction.

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