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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the description sensibly spends its words elsewhere: it discloses that records move through a lifecycle with a 'superseded' terminal state, which tells the agent that historical and replaced decisions are included in results. It does not mention pagination or retention behavior, so it stops short of full disclosure.

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 short sentences, front-loaded with the resource and its lifecycle, followed by the practical question it answers. Nothing is redundant or filler.

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 and annotations cover the safety profile, so the description needn't explain return values. Still, for a six-parameter tool with zero required parameters, it omits what happens with no filters (all decisions? default limit of 50?) and how filters combine, leaving an agent to guess at default behavior.

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 only 17%, so the description must carry the burden. It does explain the meaning of the status lifecycle values and hints at date filtering via 'per-period', but the action enum (none/upgrade/downgrade/handoff_custom), limit bounds, and business_id scoping are left entirely to the schema.

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: 'List per-period automatic plan right-size decisions', and names the lifecycle states returned (dry_run -> notified -> kept | applied | superseded). This clearly separates the tool from generic plan/history siblings like list_plans or list_subscription_history, though it never names an alternative 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?

The line 'Answers "is this business about to get right-sized"' gives an implied query intent that helps an agent decide to reach for it. There is no when-not guidance, no mention of which sibling to use for the plan catalog versus decision history, and no note that all filters are optional.

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