debuggerVariables

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the attached-session prerequisite and the node-expansion behavior for complex values, which is useful. It doesn't disclose what happens if no session is attached or whether the variable list is sorted, but the annotations lower the bar.

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?

Two sentences, no filler. The core purpose is front-loaded, the prerequisite is stated, and the routing to debuggerChildVariables is included. Every sentence earns its place.

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?

For a read-only variable-listing tool with a single documented parameter and no output schema, the description covers the essential context: what it returns, the session prerequisite, and how complex values are handled. It could mention error behavior when no session is attached, but that's a minor gap given the annotations.

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 description coverage is 100%, so the schema already documents the 'parents' parameter. The description doesn't add much beyond the schema—it doesn't explain what 'parents' means in the context of the current stack frame or how to use it. Baseline 3 is appropriate since the schema carries the parameter documentation.

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 what the tool returns: variables visible in the current stack frame with their values. It also distinguishes itself from debuggerChildVariables by noting that structures/tables come back as nodes to open with that sibling. It doesn't explicitly name the sibling in the description, but the reference is unambiguous.

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 a clear prerequisite ('Needs an attached session') and tells the agent when to use debuggerChildVariables instead (for structures/tables). It doesn't explicitly say 'use this when you need flat variables' but the context is clear enough.

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