add_marker

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

With no annotations, the description bears the full disclosure burden. It usefully explains the default placement (start frame when frame_id is omitted), but says nothing about persistence, required state/permissions, whether the marker is selected after creation, or what is returned.

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?

One short sentence, front-loaded with the action, and the parenthetical default is immediately useful. No wasted words, though the brevity is partly the source of the coverage gaps.

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 5-parameter mutation tool with no annotations and no output schema, the description is too thin: only the frame_id default is covered, leaving required state and the meaning of four parameters unexplained.

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 explain the 5 parameters. It only clarifies frame_id's null default; name, note, color and duration are left entirely undocumented, including what a 'duration' of 1 means.

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 (add) plus resource (marker) and the target scope (the active timeline). It is clearly distinguishable from get_markers and delete_marker, though it doesn't explicitly name those siblings.

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?

'Active timeline' implies a prerequisite (a timeline must be current) and nudges toward set_current_timeline workflows, but the description never states when to use this versus alternatives or what happens if no timeline is active.

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