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

Even with annotations present, the description adds substantial non-obvious behavior: invoke runs uninstalled MCPs one-off, credential needs return a connect link, empty wallet returns a checkout/top-up link followed by retry, and install has a hidden 'one-off install behind invoke' effect. Nothing contradicts 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 well structured, moving from purpose to core flow, then key invoke behavior, install-vs-invoke guidance, permissions, and the prompt library. Each section earns its place for a multi-action tool, though some wording is redundant and the sentence about capability-request examples could be trimmed.

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 highly complex 23-parameter dispatch tool with no output schema, the description covers the major contextual gaps: discovery flow, per-tool profile contents, one-off execution, auth and payment outcomes, permission requirements, billing action semantics, and the prompt library. It is genuinely complete for agent decision-making.

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 0% schema description coverage and 23 parameters, the description adds real meaning to the core action enum (search, describe, invoke, install, list_tools, etc.), tool_id, mcp_id, arguments, and prompt-related parameters. However, several parameters like limit, immediate, cancel_reason, and prompt_vars are not explicitly explained, so it does not fully compensate for the schema gap.

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 tool as 'the official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them,' which is a specific verb+resource statement. It also lays out the core search→describe→invoke flow, distinguishing it from sibling tools like authenticate or show_version.

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 when-to-use guidance: 'prefer invoke for a single/occasional use' versus 'Use install only to make an MCP PERMANENT in the active toolkit,' and clarifies that 'list_tools lists what is callable right now.' It also states that writes require workspace owner/admin, which is critical selection context.

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