Search the fleet index

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint). The description adds real behavioral context beyond that: results include connectivity state only when connectivity indexing is enabled, and the operation requires account-level fleet indexing to be enabled. It stops short of describing result volume or pagination behavior.

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?

Well front-loaded: purpose, then the unique use case, then syntax examples, then the prerequisite. Every segment earns its place, though the run-on example block is slightly dense to parse.

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 query tool with no output schema, the description covers what it returns, the key precondition, and query syntax. It is complete enough to invoke correctly, with only pagination semantics (next_token) left entirely to the schema.

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?

With 67% schema coverage, the query and next_token parameters are documented in the schema, but the description adds substantive meaning for the query parameter via field:value syntax and four concrete examples (connectivity.connected, thingName wildcard, attributes.site, shadow.reported.firmware). max_results is left to the schema, which is acceptable.

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?

States a specific verb and resource ('Runs a fleet-indexing query (AWS_Things index)') and clarifies it returns matching things with connectivity state. It claims unique scope with 'only way to answer which devices are offline right now', which distinguishes it from plain listing siblings, though it never names list_things explicitly.

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 frames the key use case ('which devices are offline right now') and states a hard precondition ('Requires fleet indexing to be enabled on the account'). It does not directly contrast with list_things or describe_thing, so the agent must infer when the simpler siblings suffice.

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