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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It merely states 'Update an Outlook Calendar event' without explaining whether it performs partial updates, requires permissions, or what effects it has. The description adds no behavioral context beyond the verb itself.

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?

The description is extremely short, but it is under-specification rather than efficient conciseness. It essentially restates the tool name ('update_outlook_event' → 'Update an Outlook Calendar event') without adding new information, so it fails to earn its place.

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?

Given no annotations, no output schema, and 0% parameter coverage, the description is completely inadequate. It does not explain the update scope, parameter meaning, return value, or any prerequisites. A mutation tool with these gaps requires substantially more context to be usable.

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 0%, so the description must compensate by explaining parameters. It does not mention any parameters, nor does it clarify that 'eventId' is required or how 'start', 'end', and 'summary' should be formatted. This leaves the agent with no additional semantic insight over the bare schema.

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 clearly identifies the action (update) and the resource (an Outlook Calendar event), which distinguishes it from create/delete operations and other calendar tools. However, it lacks detail about what aspects can be updated, so it's clear but not maximally specific.

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 alternatives like 'create_outlook_event', 'delete_outlook_event', or 'update_calendar_event'. It does not mention any prerequisites, exclusions, or specific use cases, leaving the agent to infer usage from the name alone.

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