Take a picture in IPGMovie

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

Annotations already state readOnlyHint=false, destructiveHint=false, openWorldHint=false, and the description adds non-obvious behavioral context: passing time_s during a run makes IPGMovie stop following the run, and erg requires the result file to contain vehicle motion prepared via cm_output_quantities_edit. It does not cover rate limits or exact output format, so 4 rather than 5.

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 front-loaded with the core action and then explains the three modes and the side-effect warning in compact sentences. Every sentence carries a condition or prerequisite, so it earns its length.

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?

With five optional parameters fully documented in the schema and safety annotations present, the description fills the remaining behavioral and usage gaps: return type, run-context rules, erg prerequisite, and the stop-following side effect. Nothing critical for correct invocation appears 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 coverage is 100%, so baseline is 3. The description nevertheless adds semantic constraints beyond the schema: time_s is only valid after a run, width/height are ignored during a run, and erg must reference a result file with vehicle motion. This is useful contextual meaning, yielding a 4.

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 the tool captures IPGMovie's 3D view and returns it as an image, giving a clear verb and resource. It does not explicitly differentiate itself from sibling tools such as cm_movie_open or cm_live, so it stops short of a 5.

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?

It gives explicit conditional guidance: after a run use time_s for any moment (if IPGMovie was open), during a run omit time_s and use the window as-is, and with erg replay a saved result. It also names a clear when-not: do not pass time_s during a run because it breaks run-following.

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