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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds useful behavioral context: what stats are included (uptime, signals, macro regime, backlog) and that it mirrors REST GET /health with extra context. It doesn't describe return format or error handling, but for a simple health read this is adequate.

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 two sentences, front-loaded with the core purpose, then the REST mirror, then the gating note. Every sentence earns its place, and the [META] prefix signals it's a meta/health endpoint. No waste.

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?

Given the tool has no input parameters and an output schema is present, the description covers the tool's purpose, contents, and access policy. It's complete for an agent to decide when to invoke it, and the alternative for unauthenticated liveness is spelled out.

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?

There are zero parameters, so the schema has full coverage by default. The description adds context about what the tool returns, which is sufficient for a no-argument tool. The baseline for zero params is 4, and the description meets that bar.

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 verb+resource: it provides 'Liveness + lightweight pipeline stats' with a concrete list (uptime, signals, macro regime, classifier backlog) and explicitly says it 'Mirrors REST GET /health'. This clearly distinguishes it from sibling tools like get_* which are data-specific.

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 explicitly notes it is 'Pro-gated (per tools/call rule)' and directs to 'use REST /health for unauthenticated liveness', giving a clear when-to-use and when-not-to-use alternative. This is exactly the kind of explicit guidance needed.

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