get_variable_details

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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds the scoping constraint of 'top stack frame', which is useful context. However, it does not disclose additional behavioral traits such as error behavior, side effects, or dependencies on a debugger session, which could be relevant.

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 concise sentence with no unnecessary words. It states the action and scope clearly, earning a perfect score for conciseness.

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's simplicity (one parameter), the presence of an output schema, and annotations covering safety, the description is sufficiently complete. It correctly identifies the evaluation context (top stack frame), which is the key information an agent needs. Minor gap: it doesn't explicitly mention that the tool is read-only, but annotations cover that.

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 input schema already provides a thorough description of the parameter ('Variable or attribute expression evaluated in the top frame of the active stack') with 100% coverage. The description's mention of 'variable name' adds little beyond the schema, so the baseline score of 3 applies.

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 'evaluate[s] a variable name' in a specific context ('top stack frame'), using a specific verb and resource. This differentiates it from sibling tools like evaluate_expression, which likely handles more general expressions, and get_stack_trace, which retrieves stack frames.

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 does not provide any guidance on when to use this tool versus alternatives. It lacks explicit when-to-use or when-not-to-use instructions and does not mention sibling tools or conditions that would steer an agent toward this tool.

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