mcp_health_check

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

Annotations already declare readOnlyHint=true and openWorldHint=true, which covers the safety profile. The description adds specific behavioral context: that it checks both reachability and credential validity, which is not captured by the annotations alone. This goes beyond the schema (empty) and clarifies exactly what the tool verifies, making the behavior more transparent.

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 concise, using two sentences to convey the core purpose and a parity reference. It is front-loaded with 'Health check' and immediately explains what is confirmed. There is no unnecessary detail, and both sentences earn their place.

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 diagnostic tool with no output schema, the description is essentially complete. It tells the agent what the tool does and what it verifies. It does not describe the return format (e.g., boolean, status object), but given the tool's simplicity, this is a minor gap. The annotations cover the read-only nature, so nothing critical is missing for calling 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 has zero parameters and schema coverage is 100% (empty schema). According to calibration, a baseline of 4 is appropriate for 0 params. The description adds no parameter-specific semantics, but none are needed. It correctly focuses on the action rather than inputs.

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 purpose: 'confirm the instance is reachable and the configured credentials resolve to a valid user.' It uses a specific verb ('confirm') and a specific resource (instance/credentials), and it's distinct from the many sibling tools that operate on specific entities. The reference to 'Parity with ServiceNow MCP Health Check' reinforces its identity.

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 implicitly communicates when to use this tool: for verifying connectivity and authentication. It does not explicitly state when not to use it or name alternatives, but given the tool's unique diagnostic nature among a large set of operational tools, the usage context is clear. The 'Parity' note adds context that it aligns with a known MCP standard, aiding agent decision-making.

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