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

Annotations declare a non-read-only but non-destructive write, and the description adds real behavioral detail beyond them: default ordering is last on the target day unless index places it, and a null date unschedules the activity. It does not cover permissions, effects on the positions of other activities, or what a partial move (date same, lane changed) does.

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?

A single tight sentence that front-loads the move and then the ordering default; every clause carries information. The stacked parentheticals make it slightly dense to scan but nothing is wasted.

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 5-param mutation with annotations and an output schema, the description covers the non-obvious semantics (unset date, index default, lane vs shared plan) that an agent would otherwise have to guess. Remaining unknowns, such as reindexing side effects, are minor.

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 only 40% schema coverage, the description compensates well for the ambiguous params: it defines index semantics (0 = first, default = last), laneId semantics (lane vs shared plan vs omitted = unchanged), and date's null meaning. tripId and activityId carry no description-level clarification, but tripId already notes its source (list_trips) in 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 (move an activity) plus the exact scope of the change: another day, null for unscheduled, into a lane or back to the shared plan. This clearly separates it from update_activity (field edits) and add_activity (creation) without needing the 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?

Usage context is implied by the described capability (rescheduling, lane reassignment), but there is no explicit statement of when to prefer this over update_activity or remove_activity, and no prerequisites or failure conditions mentioned.

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