evaluate

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

With no annotations, the description carries the full burden. It explains the evaluation context and common uses, but does not warn that arbitrary JavaScript evaluation may have side effects on the debuggee state (e.g., calling methods can mutate). This is a notable gap for a potentially unsafe operation.

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?

Three sentences, each earning its place: defines the action and context, enumerates use cases, and positions it relative to getScopeVariables. No fluff or repetition.

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 adequate for selecting the tool, but lacks important caveats such as side-effect risk and behavior when not paused. Since there is no output schema, the description should clarify what the evaluation returns, but this is partially mitigated by the straightforward nature of evaluating an expression.

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 coverage is 100% for both parameters, so baseline is 3. The description adds value beyond the schema by providing concrete expression examples (this.state, JSON.stringify(obj)) and clarifying that frameIndex selects the call frame context, enhancing understanding of the expression parameter.

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 uses a specific verb ('Evaluate') and clearly identifies the resource ('any JavaScript expression in the context of the currently paused call frame'). It distinguishes itself from sibling getScopeVariables by noting it complements that tool for values not directly visible in scope.

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?

It explicitly lists use cases: inspect nested objects, call methods, compute derived values, verify conditions. It also names getScopeVariables as the complementary alternative, giving clear contextual guidance without explicit exclusions.

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