step_simulation

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

With no annotations provided, the description carries the full behavioral burden, and it does well: it discloses exact frame counting, self-contained initialization on first call, operation only on paused/stopped timelines, and error behavior on a playing timeline. It stops short of describing post-step timeline state or what happens when no observe arguments are provided, but the disclosed behavior is already substantial.

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?

The description is longer than average, but nearly every sentence earns its place: core behavior is front-loaded, the play_simulation exclusion is critical, and the debug loop is a practical aid. It is slightly extended by the numbered workflow, but the structure keeps it readable and purpose-driven.

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?

Given the potential for confusion with play_simulation, pause_simulation, and stop_simulation, this description is functionally complete. It explains all three parameters, the exact behavioral contract, error conditions, and a recommended debug workflow; return-value details are covered by the output schema, so nothing essential is missing.

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 0%, so the description must compensate, and it does. It explains num_steps as 'Number of simulation frames to step,' observe_prims as prim paths returning position and velocity, and observe_joints as articulation prim paths returning joint positions. This adds real semantic value beyond the raw parameter names.

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 opens with a precise verb and resource: 'Advance the simulation by exactly N physics frames on a FROZEN timeline.' It also distinguishes itself from play_simulation by explicitly framing step as the frozen-timeline counterpart, so an agent can select it correctly without inferring from the name.

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 explicit when-to-use and when-not-to-use guidance: do NOT call play_simulation before or during the debug loop, step errors if the timeline is playing, and play_simulation is reserved for final continuous runs. The included debug loop further demonstrates the intended sequencing with sibling tools like set_joint_positions and get_physics_state.

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