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

Beyond the annotations (readOnlyHint=false, openWorldHint=true), the description reveals critical behaviors: invoke works even when MCP is not installed and has one-off execution semantics; returns connect/checkout links for auth/payment; requires workspace owner/admin for writes; and flags installed_in_toolkit vs installed_in_workspace. This is rich, actionable transparency 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 densely informative, covering the core flow, edge cases (uninstalled MCPs, payment links), permission requirements, and the prompt library. It is front-loaded with the main purpose and uses every sentence to add value. While it could be split into structured points, the length is justified given the tool's complexity.

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 with 14 actions, 23 parameters, no output schema, and no parameter descriptions, the description provides substantial context: the search-describe-invoke workflow, install vs invoke behavior, permission requirements, and prompt operations. However, it omits details on some actions (e.g., resume, list_tools specifics), output structures, and error handling, so it falls short of fully complete for such a complex tool.

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?

The input schema has 23 parameters with zero descriptions (0% coverage). The description explains high-level concepts (action values like search/describe/invoke) and some parameters implicitly (mcp_id, tool_id, arguments), but many parameters (e.g., immediate, tier_slug, prompt_vars, cancel_reason) are never explained. The description does not compensate for the lack of schema documentation, leaving the agent uncertain about parameter formats and meanings.

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 the tool's role as the MCP marketplace and prompt library, with specific actions and flow. However, it doesn't explicitly differentiate itself from sibling tools like authenticate or report_bug (which also appear as actions within this tool), so the purpose is clear but not sharply distinguished from alternatives.

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 explicit guidance on when to use invoke vs install ('prefer invoke for a single/occasional use... use install only to make an MCP PERMANENT'), and explains the core search→describe→invoke flow. It also mentions billing via subscribe/cancel and when to request a new MCP. However, it doesn't compare this tool to sibling tools like connect or authenticate, leaving some ambiguity about when to use those instead.

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