health_summary

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description need not repeat those. It adds behavioral context by stating it 'aggregates sessions, machines, and pools into a compact status,' which goes beyond the annotations. It also hints at the return content (session totals, problem machines, pool availability), though it does not detail format or pagination—acceptable given the read-only, idempotent nature.

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?

Two sentences with zero waste. The core summary is front-loaded, and the drill-down guidance follows naturally. Every word contributes value.

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 read-only summary tool with no output schema, the description adequately covers what it returns and how to proceed. It mentions the aggregated categories and points to follow-up tools. It does not mention limits like time ranges or defaults beyond what the schema covers, but these are not critical for a health summary. Overall, it is sufficiently 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 single parameter 'target' is fully described in the schema ('Horizon target from config.yaml; omit to use the default.'), so schema coverage is 100%. The description adds no further parameter semantics, which is fine—the baseline of 3 applies because the schema does the heavy lifting.

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 clear purpose: 'One-glance Horizon VDI health: session totals by state, problem machines, pool availability.' It names the resource (Horizon VDI) and the aggregated content, and distinguishes itself from siblings by positioning as the 'first thing to call for how is VDI right now?' and pointing to drill-down tools like machine_list and session_list.

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?

Explicitly tells when to use it ('first thing to call for how is VDI right now?') and when to use alternatives ('Drill into problems with machine_list --state or session_list'). This gives clear routing and avoids confusion with the many sibling tools.

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