evaluate_on_call_frame

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes side effects ('read-only by default; can modify state if expression includes mutations'), prerequisites, and return values ('expression result with type and value'). However, it lacks details on error handling or specific constraints beyond the prerequisites.

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 front-loaded with key information and uses semicolons efficiently to separate concepts. Every sentence adds value, covering purpose, behavior, prerequisites, returns, usage context, and alternatives without redundancy. It's appropriately sized for the tool's complexity.

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 moderate complexity (1 parameter, no output schema, no annotations), the description is mostly complete. It covers purpose, usage, behavior, and alternatives well. However, without an output schema, it could benefit from more detail on return format (e.g., structure of 'type and value'), but it's sufficient for basic 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 input schema has 100% description coverage, providing details on the 'expression' parameter. The description adds minimal value beyond the schema by mentioning 'accessing local variables and call stack' and 'JavaScript expression', but it doesn't elaborate on parameter semantics like expression complexity limits or examples. Baseline 3 is appropriate given high schema 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 specific action ('evaluates JavaScript expressions') and resource ('within the scope of a paused call frame'), distinguishing it from sibling tools like 'evaluate_js' for global scope evaluation. It explicitly mentions accessing local variables and call stack, which defines its unique 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?

The description provides explicit guidance on when to use this tool ('during debugging' with prerequisites like 'requires debugger to be paused at a breakpoint with active call frame') and when not to use it (alternatives like 'evaluate_js' for global scope evaluation and 'step_over' to advance without evaluation). It clearly differentiates from sibling tools.

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