set_playback_range

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

With no annotations, the description carries the full burden and does so well: it discloses that an out-of-global-range value silently widens the global frame range (unlike graphical Houdini which clamps), that the reply carries `frame_range_widened` with before/after values, and that this moves $FSTART/$FEND so default-ranged ROPs and caches follow. That is substantive mutation-impact disclosure, short only of dirty-state or permission notes.

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?

Front-loaded with the core action, then a compact paragraph of consequences and an Args list — every part is relevant. The Houdini-clamping parenthetical is informative rather than padding, though the prose could be trimmed marginally.

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 usefully surfaces the `frame_range_widened` reply field and the downstream effects on ROPs/caches. For a two-number mutation tool, this is close to what an agent needs, missing only explicit guidance on sibling selection.

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, but the Args block only restates the names ('start: Start frame', 'end: End frame'), adding units and little else. The aggregate widening narrative touches the semantics of the pair, which lifts it above a bare restatement, but per-parameter meaning remains thin.

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 first sentence names a specific verb and resource ('Set the playback range') and grounds it with 'green bar in the timeline', so the target is unambiguous. It does not, however, differentiate from near-siblings like set_frame_range, set_frame, or playbar_control, which is what would be needed for 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?

The description explains consequences (widening the global range, side effects on $FSTART/$FEND and ROP/cache defaults), which indirectly tells an agent when the tool is safe or risky to call. But it never states when to prefer it over set_frame_range, set_frame, or playbar_control, so routing guidance is only implied.

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