summarize_health_events

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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely useful behavior beyond that: output is counts only, and the token-cost rationale for choosing this over listing tools.

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?

Front-loaded with the one-line purpose and the cost rationale before the Args block. The three example prompts are somewhat padded — two would have made the point — but nothing is misleading or wasted.

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?

An output schema exists so return shape need not be described, and the description nonetheless states the return is counts only. With both optional params explained and usage triggers given, an agent has everything needed to call this correctly.

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 coverage is 0% with no enums, so the description must carry the parameters — and it does, enumerating the four allowed group_by values ('service', 'status', 'category', 'region') and clarifying that include_closed adds resolved events to open/upcoming ones. It omits the defaults (service / false) that the schema declares implicitly.

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 ("Count active AWS health events") plus the key constraint ("without returning their descriptions"). It explicitly contrasts itself with the listing siblings, so an agent can distinguish it from get_service_health / get_service_events without opening a schema.

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?

Gives a clear trigger ("is anything wrong?" questions) and a clear anti-trigger (use listing tools when full descriptions are needed), reinforced by three example prompts. It refers to alternatives by category ("Listing tools") rather than naming specific siblings, which is the only gap.

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