get_agent_required_variables

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

With no annotations, the description carries the full burden, and it delivers detailed behavioral context. It explains the return split into system_variables and dynamic_variables, clarifies that system variables are platform-injected and should never be supplied, and notes that sources/categories are included 'where possible.' This goes beyond a simple read-only list and provides valuable insight into the tool's behavior.

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 well-structured and concise. It begins with a clear summary sentence, uses bullet points to delineate variable categories, and ends with a practical usage tip and rationale. Every sentence provides useful information, with no filler or redundancy.

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 description is quite complete for a one-parameter tool, covering purpose, return structure, and usage. An output schema exists, so return-value details are covered there. However, it does not mention potential error conditions or explicitly relate to sibling tools like get_system_variables_catalog, which would enhance contextual understanding.

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 has one required parameter, agent_id, with 0% schema description coverage. The description does not mention or explain this parameter at all. While the parameter name is self-explanatory, the description adds no semantic value to the schema, so it does not compensate for the coverage gap.

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 purpose: 'List the {{variable}} placeholders an agent needs at call time.' It uses a specific action verb and resource, and distinguishes itself from siblings by detailing the two categories of variables (system and dynamic). This makes the tool's function immediately evident.

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 gives explicit guidance on when to use the tool: 'Use this before placing an outbound call to verify the dynamic_variables payload covers every required name.' It also warns 'never supply' system variables. However, it does not explicitly name alternative tools (e.g., get_system_variables_catalog) or state when not to use it, so it falls slightly short of a perfect score.

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