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

Annotations already declare destructiveHint=true and idempotentHint=true, so the bar is lower, yet the description still adds the blast radius ('tells everyone invited') and a consent prerequisite — real behavioral context beyond the structured flags. It does not address retry/idempotency semantics, but the schema's idempotency_key description covers that.

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 with zero waste: the action and its broadcast effect come first, the consent prerequisite second. Every sentence earns its place.

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 destructive mutation with an output schema (so return values need no explanation), the description covers the action, the notification side effect, and the confirmation gate. It omits edge behavior such as cancelling an already-cancelled plan, a minor gap.

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 50%: idempotency_key is well documented, while plan_id is undocumented in text but fully self-describing via uuid format and a strict pattern. The description adds no parameter-level meaning, which is acceptable given the schema carries the weight, but it neither compensates nor enriches.

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+resource ('Cancels a plan') with added scope ('the agent organizes') and a stated side effect ('tells everyone invited'). This distinguishes it from respond_plan/update_plan/leave_group well enough to route correctly, though no sibling is named 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?

Provides one prerequisite ('Needs the person's confirmation first'), which is genuine when-to-use guidance. However, it offers no alternatives for adjacent cases (declining an invite via respond_plan, or leaving a group) and no when-not-to-use condition.

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