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 states 'adds a marker' but does not mention whether this mutates existing markers at the same time, whether it creates point or span markers, if a sequence must be active, or any side effects. The schema documents parameters, not behavior, so the description is insufficient for a mutation tool.

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?

The description is a single sentence with no filler or redundancy. It is appropriately sized for the basic purpose statement, and every word contributes to conveying the action and intent. This is efficient and front-loaded.

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?

The tool has 6 parameters, 3 required, and introduces features like duration for span markers, yet the description is minimal. There is no output schema or annotations, so the description should explain return values or behavioral context. It does not mention ability to create span markers, required active sequence, or what happens on success/failure. This is incomplete for the tool's complexity.

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?

The schema already describes 100% of the parameters with meaningful details. The description adds no extra parameter semantics beyond the generic 'timeline' context. Baseline is 3 due to full schema coverage, and the description does not improve upon it.

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 action 'Adds a marker to the timeline' and the purpose 'for navigation or notes'. It is specific about the resource (timeline) and the action, but does not distinguish from the sibling tool 'add_marker_to_project_item', which also adds markers but to project items. Thus it lacks sibling differentiation.

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 implies usage for placing timeline markers for navigation or notes, but provides no explicit guidance on when to use this tool versus alternatives like 'add_marker_to_project_item', 'update_marker', or 'delete_marker'. No alternatives or exclusions are mentioned, so the usage context is only inferred.

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