auth_status

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

With no annotations, the description carries full burden and clearly discloses a key behavior: 'Does NOT hit the upstream API — purely a local cache check.' This alerts the agent that the tool is safe and fast, avoiding unnecessary network calls. It could add more detail about response format or staleness, but this is sufficient for a simple status tool.

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 three lines, front-loaded with the purpose, followed by usage guidance and a key behavioral caveat. Every sentence earns its place with no fluff. It is tightly structured and immediately readable.

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 zero-parameter status check tool, the description fully covers what it does, when to use it, and its local-cache behavior. No output schema exists, but 'Report whether' sufficiently indicates the return type. No additional context is needed for the agent to select and invoke it correctly.

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 0 parameters, so the baseline is 4. The description correctly omits parameter details since there are none, and the schema is already at 100% coverage (vacuous). No additional explanation needed.

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 begins with a specific verb 'Report' and clearly identifies the resource: 'whether the MCP currently has a usable vendor access token.' This distinguishes it from sibling tools like vendor_login and get_current_user by focusing on token availability rather than the login process or user info.

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?

Directly states when to use: 'Call this before other tools if you're unsure whether login is needed.' This gives explicit usage context and implies that other tools may require a valid token. The note 'Does NOT hit the upstream API' also guides users to prefer this tool for a quick, side-effect-free check.

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