add_marker

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

With no annotations, the description carries the full burden of behavioral disclosure. It does reveal useful behavior: frame is relative to timeline start and omitting frame defaults to the current playhead. Still, it does not describe effects on existing markers, required timeline state, or any failure behavior, leaving moderate gaps.

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?

Two sentences convey the core action and a critical parameter nuance with zero wasted words. The key action is front-loaded, and the frame guidance is compressed into a single efficient clause.

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 straightforward 5-parameter tool with an output schema, the description covers the purpose and the trickiest parameter, frame. It lacks guidance on the meaning or valid values of color, duration, and note, and does not state any context requirements. This is adequate but not fully complete.

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 add meaning to the five parameters. It explicitly explains frame, but name, note, color, and duration are left entirely to inference from their property names and defaults. This is insufficient for a tool with five parameters, even though the frame explanation is valuable.

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 immediately states the action and resource: 'Add a timeline marker.' This is a specific verb and object that clearly distinguishes the tool from siblings like delete_marker and add_track, leaving no ambiguity about its function.

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 provides clear context on when to omit the frame parameter ('use the current playhead'), which is helpful parameter-level guidance. However, it does not explicitly state when to choose this tool over alternatives or mention any exclusions or prerequisites, so tool-selection guidance remains implied.

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