Answer a received calendar invitation

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

Annotations only cover the safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true). The description goes well beyond them by disclosing the external side effect (a standard calendar reply is sent, the organizer's calendar updates), the authorization gate (organizer must be on allow_send_to), comment moderation, and the return shape { message_id, warnings }.

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 tight sentences with zero filler: capability first, routing/exclusion second, constraints and return shape last. Every clause carries information an agent needs.

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 mutation tool with no output schema, the description covers the action, the side effect on the organizer, the authorization prerequisite, the alternative tool to avoid, and the returned fields. Nothing material is left for the agent to infer.

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 100%, so the baseline is 3. The description adds real meaning beyond the schema for `comment` (it is reviewed like any mail, i.e. subject to moderation) and clarifies where `id` comes from. It does not elaborate further on `response`, but the enum is self-explanatory.

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 set (accept/decline/tentative) against a specific resource (calendar invitation you received), and explicitly distinguishes itself from send_message as the wrong path for invitations. An agent can identify the operation without opening the 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 explicit when-to-use context ("read_message shows it under invitation") and an explicit when-not/alternative ("do not answer invitations with send_message"). The precondition that the organizer must be on allow_send_to is stated up front.

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