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

Annotations already declare readOnlyHint=true, and the description adds meaningful behavioral context: it returns events best-match-first, includes a timezone, marks readOnly events as not editable/deletable, and explains the ambiguous flag for ties. It also clarifies that two days of the same recurring event are not ambiguous. This goes well beyond the annotations.

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 dense but well-organized: it front-loads the core purpose and the key alternative, then explains defaults, filters, and result semantics in a logical order. Every sentence earns its place, and there is no fluff.

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 read-only search tool with 100% schema coverage and no output schema, the description covers the essential context: what it searches, the default window, how to widen it, optional filters, result ordering, timezone, readOnly caveat, and ambiguity handling. Nothing an agent needs to call it correctly 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 description coverage is 100%, so the schema already documents all six parameters. The description adds value by explaining the default date window (past week through next 30 days), the ISO format for from/to, and the meaning of the readOnly flag in results. It doesn't add much beyond the schema for areaId/activityTypeId/timeOfDay, but the defaults and result semantics are useful.

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 states a specific verb ('Search for, look up, or locate') and a specific resource ('SCHEDULED events by name'), and explicitly distinguishes itself from un-timed Inbox blocks. It also names the sibling tool get_schedule as the alternative for a different resource, so an agent can tell them apart without opening schemas.

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?

The description explicitly says when to use this tool ('when you do not have an id') and when not to ('For an un-timed Inbox block, use get_schedule with includeBacklog: true and backlogQuery'). It also explains the default search window and how to widen it, plus optional filters, which is clear context for choosing this tool.

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