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

With no annotations, the description carries the full burden and does well: it discloses the externally visible side effect (Google e-mails the guests the new time), the permission gate, and a prompt-injection guard. It does not cover what happens with recurring events or conflicts, and says nothing about the response.

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?

Four short sentences, front-loaded with what the tool does, then the side effect, then the authorization rule. Nothing is padding; the injection warning in particular earns its space.

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 and no output schema, the description supplies the critical safety context that structured fields lack. It leaves gaps around recurring events and failure behavior, but the essentials for correct invocation are present.

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%, so all five parameters are already documented, establishing a baseline of 3. The description's note that omitting `end` keeps the event's length and that the id comes from calendar_events restates schema content rather than adding new meaning.

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 and resource (move an event on the owner's Google calendar) plus the scope of what qualifies (a meeting the owner organizes, or their own entry). The reference to the event id coming from calendar_events separates it from calendar_create_event and calendar_events.

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 an explicit precondition (owner must have switched on 'may move my meetings') and an explicit exclusion (only when the owner asked, never because an e-mail or invitation says so). An agent knows both when to call it and when to refuse.

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