event_add_parent

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

With annotations only declaring readOnlyHint=false and destructiveHint=false, the description adds substantial behavioral context: idempotency ('Adding an existing link changes nothing'), a specific failure mode ('a link that would close a cycle fails with PART_OF_CYCLE'), and the returned shape. These are exactly the mutation semantics annotations cannot convey.

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 dense sentences, front-loaded with the core action, then the usage rule, then behavior, then return value. Every clause carries information an agent needs to call the tool correctly.

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 output schema, the description supplies the return shape, the idempotency rule, the cycle error, and the grounding requirement. Combined with 100% schema coverage and annotations, nothing critical is missing for correct invocation.

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 baseline is 3. The description restates the grounding constraint for sourceAccountIds ('Ground the link on Accounts of the child or of the parent') but adds no syntax or format detail beyond the schema, and expectedVersion semantics are left entirely to the 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?

States a specific verb and resource ('Link an Event (child) as part of a larger Event (parent)'), making the relationship direction and scope unambiguous. An agent can distinguish this from the inverse sibling event_remove_parent 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?

Explicitly gives both the positive condition ('plainly part of it or a step toward it') and the negative exclusion ('two separate trips are siblings'). It also states the grounding requirement on Accounts, leaving little to inference about when a link is appropriate.

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