three_live_sim

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and openWorldHint=false; the description adds that execution is deterministic and ticked at 60 Hz, which is genuinely useful behavioral context. It omits notable side effects the schema reveals, such as writing a filmstrip file to disk via outputStripPath, and says nothing about runtime cost or failure modes for a physics simulation. Given annotation coverage, this is adequate but not rich.

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?

It is a single front-loaded sentence with no filler sentences, which is good. However, '60 Hz' appears twice in near-redundant form ('60 Hz xr-live-sim rigid-body physics ... deterministically at 60 Hz'), and the dense keyword pile of feature nouns is harder to parse than a structured list would be.

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 7-parameter tool with no required inputs and no output schema, the description should clarify what the caller gets back (simulation results vs. filmstrip image blocks), what happens when neither code nor inputPath is supplied, and that file output is a side effect. None of that is covered, so the description is complete on 'what it simulates' but thin on operational behavior.

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 every parameter is already documented in the schema, including the action event types and the code/inputPath alternative. The description adds no parameter-level meaning beyond what the schema states, so the baseline of 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?

The description leads with a specific verb ('Simulate') and enumerates the concrete domains covered: KHR_interactivity graphs, orbit/explode traits, rigid-body physics, character controllers, steering agents, hit zones, and objectives. An agent knows what the tool produces (a deterministic 60 Hz simulation). It does not, however, distinguish this from siblings like three_live_render or three_live_validate, so the differentiation requirement for a 5 is unmet.

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?

There is no explicit when-to-use guidance, no statement of when NOT to use it, and no mention of the sibling tools (validate/render/convert) that an agent would need to choose between. Usage is only implied by the verb 'Simulate', leaving the selection decision to inference.

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