Create region

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

With no annotations, the description carries the full burden and does add one valuable trait: 'The arrangement itself is unchanged,' clarifying this is a non-destructive labeling operation. It still omits key behavior – what happens when no track contains the range, whether a duplicate name overwrites, permission needs, or what is returned.

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?

Two short sentences, front-loaded with the action and scope, with the second sentence delivering a distinct and useful non-obvious fact. No filler; every clause earns its place.

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?

No output schema exists, so the description need not explain return values, and the schema covers all parameters. The core creation semantics and the non-mutation guarantee are present, though edge-case behavior (no containing clip, name collision) is left unaddressed.

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 five parameters including units, ordering constraint (end must be after start), and path semantics. The description adds no parameter-level detail beyond what the schema provides, so the 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 ('Creates a named region'), plus the precise scope condition ('from a timeline range on every track whose clip fully contains it'). It anchors to the GUI's Create Region command, though it never explicitly distinguishes itself from the sibling set_region, so sibling differentiation is implicit rather than stated.

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 gives a real applicability condition – only tracks whose clip fully contains the range are affected – which implies when the tool is and isn't useful. However, it names no alternative (e.g. set_region) and gives no prerequisites or when-not guidance, so the agent must infer the routing.

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