add_to_timeline

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

No annotations are provided, so the description carries the burden. It discloses destructive overwrite behavior, insert semantics, and a confirmation check. However, it omits other potential side effects like track creation or permissions.

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?

Three sentences, front-loaded with the core action. The phrase 'confirm the clip count grew' is a behavior detail but not excessive. No redundancy or filler.

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 or annotations, but the description gives purpose, mode behavior, and a prerequisite for item_id. It lacks context about needing an active sequence or handling invalid track indices, but is adequate for a simple tool.

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 covers 60% of parameters with descriptions. The description adds meaning by explaining mode behavior beyond the enum names and suggesting list_project_items for item_id. It does not address track_type or time_seconds beyond the schema.

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 clearly states the tool's action: 'Place a project item onto a track at a given time' and adds a verification step. This distinguishes it from siblings like move_clip or remove_clip.

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?

Provides clear context for the two modes ('Overwrite replaces whatever is already there; insert pushes later clips further down the track') and directs users to list_project_items for the item ID, but does not explicitly mention when to use this tool over alternatives.

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