evite_send_message

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

The description discloses key behaviors beyond the readOnlyHint annotation: it actually notifies the guest, is sent as the host, uses Firebase rather than REST, and is confirm-gated with a dry-run preview. This is rich, non-redundant context.

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 sentences, front-loaded with the primary action, then a constraint, then the confirm behavior. No filler; every sentence provides necessary information.

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?

The description is complete for a mutation tool: it explains the purpose, the sender/authorization constraint, the delivery mechanism, and the confirmation requirement. Given the rich schema and annotations, nothing important is missing.

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 covers 100% of parameters, so baseline is 3. The description adds meaning to the confirm parameter by explaining that without confirm:true, the tool returns a dry-run preview and sends nothing—this goes beyond the schema's simple 'Must be true to proceed.'

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?

The description opens with a specific verb+resource+scope: 'Send a private message to one Evite event guest.' It clearly distinguishes from siblings like evite_broadcast (multiple guests) and evite_list_messages (reading messages) by emphasizing 'one guest' and 'private message.'

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 clear contextual guidance: only the host can use it, and confirm=true is required. This effectively tells the agent when the tool is applicable and what prerequisite must be met, though it does not explicitly name alternatives or exclusions.

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