marker_add_region

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

No annotations are provided, and the description does not disclose behavioral traits such as side effects, error conditions, or whether the operation is destructive. The agent is left uninformed about what happens after the region is added.

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 extremely concise, using two sentences for purpose and guidance, followed by a list of parameter definitions. Every part carries weight, with no redundant or irrelevant information.

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?

Given the tool has 6 parameters, required start and end, and no output schema or annotations, the description is insufficient. It lacks details on return values, error handling, and what constitutes a valid region addition.

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 description adds meaning beyond the schema by specifying units for start and end (seconds), ranges for color values (0-255), and a label for name. This compensates for the schema's lack of descriptions (0% coverage).

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 (Add region) and includes a helpful sibling differentiation by recommending add_markers_batch for multiple operations. However, it does not define what a 'region' is in this context, leaving some ambiguity.

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 a single usage guideline: 'Prefer add_markers_batch for multiple.' This is useful for one scenario but lacks broader guidance on when to use this tool versus other marker-related tools, or context around prerequisites.

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