calendar_add

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

With no annotations and no output schema, the description carries the full burden. It usefully discloses the verbatim-title rule, the personal-calendar default, and the NO_REPLY output convention — which is the only hint about return behavior — but says nothing about error handling, duplicate events, date validation, or what a successful result looks like beyond the NO_REPLY special case.

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?

Three front-loaded sentences with no filler: scope and exclusion first, then the output-handling rule. Every sentence changes what the agent does.

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 five-optional-parameter creation tool with no output schema, the description covers the two things the schema cannot: sibling disambiguation and the NO_REPLY response protocol. Failure/validation behavior is the main remaining gap.

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 defines all five parameters in detail, including the verbatim-title instruction and the empty-means-personal default. The description restates the title-preservation and personal-calendar semantics but adds no format, ordering, or interaction details beyond the schema; baseline 3 applies.

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 (add event), narrows the scope to plain/non-concert events, and names the sibling that handles the excluded case (concert_add). An agent can route between calendar_add and concert_add without opening either schema.

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?

Explicit exclusion with a named alternative: 'For a concert ticket use concert_add instead.' The positive case is only implied by 'plain (non-concert) event', and no guidance is given relative to the other siblings (event_delete, queue_status), but the key routing decision is unambiguous.

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