Assess fleet health

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

Annotations already declare readOnly/idempotent/non-destructive, so the 'never changes anything' line is partly redundant, but the description adds genuine behavioral context: worst-first ranking, per-code summary, and that connectivity is only assessed when the fleet index supplies it. No permission or rate-limit detail, but the added nuance is real.

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?

Three sentences, front-loaded with the core action, then output shape, then safety posture, then input modes. No filler and nothing an agent needs is buried.

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?

With no output schema, the description carries the return-value burden and does so (findings ranked worst-first, per-code summary). Combined with the complete input schema and annotations, an agent has everything needed to invoke and interpret this tool.

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?

Schema description coverage is 100%, so every parameter is already documented, including mutual exclusivity of query vs thing_names and the per-thing cost of include_certificates. The description only echoes the list-or-query choice, so the baseline 3 applies.

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?

Specific verb (diagnostic sweep) plus resource (things/fleet) and an explicit enumeration of what is checked: shadow freshness, convergence, certificate status/expiry, connectivity. It clearly distinguishes itself from siblings like search_fleet_index (selection only) and inspect_thing_certificates (certificates only).

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?

States the two accepted input modes (explicit thing_names list or fleet-index query) and that findings come back ranked, which tells the agent when this is the right call. It does not, however, explicitly contrast with sibling diagnostics or state when NOT to use it.

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