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

No annotations are provided, so the description carries the full behavioral burden, yet it discloses nothing: not which fields are mutable, whether the update is partial or wholesale, whether it needs event IDs or permissions, or whether changes are reversible. It signals only that a mutation occurs, which is the bare minimum.

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 with no bloat, so it is concise. However, the front-loaded portion ('Run Google calendar action') is filler that delays the only informative token, so it is not optimally structured despite its brevity.

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 only a vague freeform 'detail' parameter, the description is too thin. An agent cannot determine the required inputs (which event, which fields), the side effects, or the expected result from this definition alone.

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?

With a single parameter at 100% schema description coverage, the schema already documents 'detail' as 'Task-specific details from the objective.' Baseline 3 applies; the description adds no meaning about how to populate this freeform field, but the schema coverage means the parameter is not undocumented.

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 contains a recognizable verb+resource ('update event') but wraps it in generic filler ('Run Google calendar action:'). It distinguishes the operation from siblings like calendar__add_event and calendar__delete_event only by the verb, with no indication of what an 'update' covers or how the target event is identified.

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 calendar__add_event, calendar__delete_event, or the read-only check_events tools. No prerequisites, no exclusions, no context — the agent must infer everything from the name.

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