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

With no annotations, the description carries the full behavioral burden, yet it only implies a mutation via the word 'add'. It says nothing about required inputs for a calendar event, authentication, whether the event lands on a default calendar, or whether the action is reversible.

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?

It is a single short sentence, so it is not bloated, but the 'Run Google calendar action:' prefix is filler that consumes the front-loaded position without conveying information. Under-specification, not length, is the problem.

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 annotations, no output schema, and zero required parameters documented, the description leaves critical gaps: what fields define the event, which calendar it targets, and what happens on success. It is too thin to call the tool correctly with confidence.

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 100% for the single 'detail' parameter, so the schema already documents it and the baseline is 3. The description adds no meaning about what 'detail' should contain for an add-event action, so it does not exceed that baseline.

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 names a verb and resource ('add event' on Google calendar), which is enough to distinguish it from siblings like delete_event and update_event. However, the boilerplate prefix 'Run Google calendar action:' adds no information and the phrasing is a generic wrapper rather than a specific statement of what the tool does.

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?

There is no guidance on when to use this tool versus update_event, delete_event, or the check_events_* siblings, nor any mention of prerequisites or conditions. The agent must infer usage entirely from the tool name.

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