fantastical_add_event

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

No annotations are supplied, so the description carries the full behavioral burden. It discloses that the feature is Beta and that input is parsed from free text, but says nothing about what happens with ambiguous parses, whether the event is written to a default calendar, whether the call can fail silently, or what the response returns.

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?

What is present is front-loaded and free of padding, but the text terminates mid-example and mid-parenthetical, leaving an incomplete sentence. Structure is sound; completeness of the sentence is not.

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 an empty parameter object, the description should explain how the free-text input is supplied, which account or calendar is targeted, and what confirmation is returned. The available text stops before any of that.

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 zero declared parameters the baseline is 4, but the description explicitly promises a natural-language input string ('from one sentence, as typed in Fantastical's own field') while the schema exposes no properties at all. That discrepancy lowers the score, since an agent cannot tell from the schema where that sentence should be passed.

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 and resource (adds an event or a task) and names the target system (Fantastical), and the 'from one sentence' framing distinguishes it from structured siblings like create_calendar_event or m365_create_event that take discrete fields. The sentence is cut off mid-example, so the scope is clear but not fully delivered.

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?

Implied guidance is present: use this when you have a single natural-language phrase as typed into Fantastical's own field rather than structured date/title fields. However, it never explicitly says when to prefer this over create_calendar_event or outlook_calendar_create_event, nor does it state prerequisites such as a connected Fantastical account.

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