health_summary

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds value by explaining the aggregated nature ('Aggregates sessions, machines, and pools into a compact status') and presenting it as a high-level overview, which is helpful beyond the annotations.

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 compact and well-structured: a clear one-line purpose, a usage recommendation, and a brief parameter explanation. Every sentence contributes useful information, and the format is highly scannable with sections for the summary and arguments.

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 tool with one optional parameter, no output schema, and read-only semantics, this description is fully adequate. It states what the tool returns (session totals, problem machines, pool availability), when to use it, and how to drill further. No critical information is missing.

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 schema only defines 'target' as an optional string with default null and no description. The description compensates: 'Horizon target from config.yaml; omit to use the default.' This adds contextual meaning regarding where the value comes from and how to omit it, which is directly useful and covers the single parameter.

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 '[READ] One-glance Horizon VDI health: session totals by state, problem machines, pool availability.' This specifies a clear verb (health summary) and resource scope (Horizon VDI health), and distinguishes itself from sibling tools like session_list and machine_list by offering an aggregated overview rather than detailed data.

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?

It explicitly states 'The first thing to call for "how is VDI right now?"' and then directs users to 'Drill into problems with machine_list --state or session_list.' This provides both when to use and clear alternatives, fully satisfying the guidance requirement.

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