agent_arrange_timeline

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

The annotations already declare readOnlyHint=true and destructiveHint=false, and the description is consistent with a preview operation. It adds useful context about the max batch size of 32 and inter-batch checkpoints, but does not explain whether checkpoints are written, what the preview returns, or what happens beyond the batch limit.

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?

A single sentence with zero filler, front-loading the verb and key constraints. It is appropriately sized for the amount of information it chooses to include.

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 input schema has three parameters with nested object arrays and no field descriptions, and there is no output schema. One sentence is not enough to explain how to construct placements or markers, or how checkpoints should be used, so the definition is incomplete for a tool of this 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?

Schema description coverage is 0%, so the description must compensate. It mentions checkpoints and timeline mutations, but does not explain that placements is required, what markers represent, or the structure of checkpoint_paths; parameter meaning is largely left to the raw 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?

States a specific verb ('Preview') and resource ('timeline mutations'), plus a batch-size constraint. It does not explicitly distinguish the tool from nearby siblings like agent_arrange_preview or agent_apply, so it is clear but not sibling-differentiating.

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 says it previews timeline mutations but gives no when-to-use guidance, exclusions, or alternatives. It does not explain whether to call this before agent_apply, or how it relates to agent_arrange_preview.

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