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

Rich behavioral disclosure beyond annotations: 'invoke works even when the MCP is NOT installed — it runs the tool pontualmente (one-off), without adding the MCP to the toolkit and without bloating the tool list'; write operations 'require workspace owner/admin'; and auth/billing edge cases are disclosed (connect link, checkout/top-up link). This adds meaningful context on side effects and permissions on top of readOnlyHint=false, openWorldHint=true. No contradiction with 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?

This is a dense wall of text with no structural aids — no bullets, no sectioning, no front-loading of the most critical decisions (install vs invoke is buried mid-paragraph). Every sentence is informative, but the lack of scannable structure makes it hard for an agent to quickly extract the key branching logic. For a description this long, formatting would dramatically improve usability.

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 extreme complexity (14 actions, 23 params, no output schema), the description covers the main flows thoroughly — search→describe→invoke, install-for-permanence, the prompt library, and auth/billing edge cases. But gaps remain: the 'resume' action is never mentioned, search/list_tools return formats are undefined, and the toolkit vs workspace installed distinction is only briefly flagged. Adequate but not complete for a tool of this scope.

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 carries the full burden, and it partially delivers: the action enum values are explained in detail (search/describe/install/invoke etc.), plus tool_id/arguments and prompt variables are contextually described. However, many of the 23 parameters are never explained — immediate, tier_slug, cancel_reason/cancel_comment, prompt_targets, conversation, request_name, report_context, limit, query — leaving significant semantic gaps for an agent.

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 states what the tool is — 'The official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them.' It identifies the resource (catalog) and the core action flow (search → describe → invoke). However, it loses a point because it is a mega-tool with 14 distinct actions (search, describe, install, invoke, subscribe, search_prompts, etc.) folded into one definition, so the purpose is clear but not singular or tightly scoped.

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?

Strong within-tool guidance: 'prefer invoke for a single/occasional use' vs 'Use install only to make an MCP PERMANENT in the active toolkit', plus the search/describe/invoke pipeline is spelled out. It also explains conditional behavior (connect link for credentials, checkout link for empty wallet). It does not, however, contrast with sibling tools like authenticate, connect, or toolkit_info, so cross-tool exclusion guidance is missing.

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