Create safety blackout chain

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

Annotations indicate readOnlyHint=false, openWorldHint=true, destructiveHint=true. The description adds valuable behavioral context beyond these flags: the chain is deterministic, Python-free at cook time, ALLOW_EXEC=0-safe, and built at the end of the master output chain (which implies it modifies the output path). It does not contradict annotations, and while it does not elaborate on the destructive implications, it sufficiently discloses the tool's construction and safety characteristics.

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?

Though the description is a long sentence, every clause provides essential information: purpose, placement, capabilities, technical mechanism, complementary tool, and return value. It is front-loaded with the core action and avoids redundant filler. The structure is efficient given the tool's complexity.

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?

The tool is complex (11 params, 0 required, no output schema). The description covers what the tool creates, where it fits in the signal chain, how it is triggered (hotkey, watchdog, emergency), the recovery behavior, the Python-free safety aspect, and explicitly enumerates the returned node paths. This fully compensates for the lack of an output schema and gives the agent a complete mental model.

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?

All 11 parameters have schema descriptions (100% coverage), so baseline is 3. The description adds a cohesive semantic layer by describing how parameters interact: 'configurable time', 'optional emergency single-frame hard-cut', 'optional hotkey + external watchdog trigger', and 'symmetric fade-in recovery'. It reinforces that 'All reactivity is parameter-driven... no Python runs at cook time', which helps the agent understand the overall parameter architecture beyond individual parameter descriptions.

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 exactly what the tool does: 'Build a live-show safety primitive at the very end of the master output chain' with specific capabilities (fade-to-black, emergency cut, hotkey, watchdog, fade-in recovery). It is a specific verb+resource, and it distinguishes from sibling create_panic by explicitly positioning itself as the 'master-output dimmer' complement.

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 clear usage context: it is for live-show safety at the end of the master output chain, and it explicitly names the alternative `create_panic` and differentiates: 'Complements create_panic (per-source kill+freeze) by being the master-output dimmer with grace, recovery, and a watchdog hook.' This is an explicit when-to-use vs. alternative guidance.

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