Add Markers Batch

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

Despite annotations already declaring the non-read-only, non-destructive, non-idempotent profile, the description adds substantial non-obvious behavior: pre-write validation and range-checking, read-back of marker count and times, fail-closed on mismatch, and an EXPERIMENTAL QE boundary that refuses Undo/Redo crossings by default and reports unknown protection for unreadable history. It even flags a limitation (no native marker reversal verification), which is exactly the kind of caveat annotations cannot convey.

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?

Purpose and scale are front-loaded in the first sentence, verification semantics follow, and the experimental QE caveat is clearly separated. It is dense but each clause carries operational weight; no filler or repetition.

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 mutation tool with full annotations and an output schema (so return values need not be explained), the description covers validation, failure mode, and Undo/Redo safety adequately. The remaining gap is sibling routing — it never tells the agent when the batch tool is preferable to add_marker or add_marker_to_project_item.

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 all five parameters (including nested marker fields and the node_id/allow_beyond_end/skip_existing_within_frames semantics) are fully documented in the schema. The description restates the 200-item cap and range-checking but adds no syntax or format meaning beyond what the schema provides, so the baseline 3 is appropriate.

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?

States a specific verb and resource with scope: 'Add up to 200 sequence or clip markers in one verified CEP request,' and parenthetically lists the workflows it serves (beat grids, chapters, silence reviews, client notes). The batch/verified framing distinguishes it from single-marker siblings, though it never names add_marker explicitly as the single-marker alternative.

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 parenthetical use cases imply when to reach for this tool, and the node_id schema note points at add_marker_to_project_item for the Premiere 25.2.3 limitation. But the description itself gives no explicit when-to-use or when-not guidance relative to add_marker, add_marker_to_project_item, or the plan_*_markers siblings, leaving selection largely to inference.

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