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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds that the tool covers all major clients and platforms, but says nothing about the form of the guidance returned (per-client breakdown vs. single recommendation) or whether it is static reference content. With annotations carrying the safety burden, 3 is appropriate.

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?

A single sentence that front-loads the purpose ('Explains which authentication mode suits FXMacroData MCP') before the enumeration. The client/platform list is long but each entry conveys real scope information, so it earns its place; the sentence is dense but not padded.

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?

No parameters and no output schema, so the description carries the disclosure load, and it does state the scope of coverage (modes plus clients/platforms). What is missing is a light hint about the shape of the answer (e.g., a per-client recommendation table), but for a zero-argument reference tool this is nearly complete.

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 tool takes zero parameters, so the baseline is 4. The description correctly implies a parameterless, all-clients answer rather than a client-scoped query, which is the only parameter semantics that could apply here.

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 names a specific subject (authentication mode selection for FXMacroData MCP) and enumerates the modes (OAuth, API key, bearer token) and client coverage (ChatGPT, Claude, VS Code/Copilot, AstrBot, Cursor, Codex, scripts, CI). That is enough for an agent to distinguish it from data-oriented siblings like mcp_capabilities or subscribe_for_mcp_access. It does not explicitly contrast itself with those siblings, so it stops short of a 5.

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 implies usage (an agent answering 'how do I authenticate to this MCP server?' should call it) but never states when to use it versus mcp_capabilities or subscribe_for_mcp_access, nor any prerequisites. The client list gives strong topical context, but no explicit when/when-not guidance is present.

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