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

Even with annotations present (readOnlyHint:false, openWorldHint:true), the description meaningfully extends beyond them. It discloses that invoke runs tools one-off 'without adding the MCP to the toolkit and without bloating the tool list', that writes (install/uninstall/subscribe/cancel and the one-off install behind invoke) require workspace owner/admin, and that invoke returns connect/checkout links requiring user action then retry. No contradiction with annotations found.

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 information-dense with genuinely useful content, but it is delivered as a single continuous run-on paragraph with no bullet points, sections, or headings. It covers three distinct domains (MCP catalog flow, billing/installs, prompt library) without structural separation. Every sentence earns its place, but the formatting undermines scannability for an agent.

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 very complex tool (23 params, 14-action enum, no output schema), the description covers the primary flows thoroughly: search→describe→invoke, install vs invoke distinction, auth ownership requirements, payment link behavior, and the separate prompt-library sub-flow. Gaps remain in peripheral actions (resume, uninstall details, cancel workflow specifics) and return-value descriptions for search/list_tools, but the core usage is well covered.

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, the description must compensate, and it does for the core flow: it maps action enum values to behaviors and explains tool_id/mcp_id/arguments usage in the search→describe→invoke flow. However, many of the 23 parameters (prompt_vars, conversation, tier_slug, cancel_reason, cancel_comment, prompt_targets, request_details, immediate, etc.) receive no semantic explanation, so compensation is only partial.

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 states a specific, multi-faceted purpose: it is the in-platform MCP catalog and execution tool ('the official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them'). It clearly distinguishes itself from siblings (authenticate, show_version, toolkit_info, sefaz_ma_dec_caixa_postal_consultar) by being the catalog/runner rather than a specific capability, and explicitly contrasts install vs invoke vs list_tools.

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?

Provides explicit when-to-use guidance: 'prefer invoke for a single/occasional use', 'Use install only to make an MCP PERMANENT in the active toolkit', and spells out the core flow 'search discovers MCPs by intent → describe returns one MCP's full profile... so you pick the right tool_id → invoke RUNS that tool'. Also covers the retry pattern (connect/checkout link then retry) and the prompt-library sub-flow, naming search_prompts/get_prompt/publish_prompt with distinct roles.

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