debug_get_stackRetrieve the current call stack from a paused Node.js debug session to inspect active frames and trace execution flow during breakpoint analysis.
Return the current call stack. Requires a paused target. Lines are 1-based.
| Name | Required | Description | Default |
|---|---|---|---|
| sessionId | No | Session id from debug_launch/debug_attach. Required when more than one session is live. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With annotations already marking this as read-only and non-destructive, the description adds minimal extra behavioral context. It does add the requirement for a paused target and the 1-based line numbering convention, but it does not clarify failure modes (e.g., what happens if no target is paused) or whether the stack is returned in any specific order. This is adequate but not rich.
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 extremely concise: two short sentences that are front-loaded with the core purpose ('Return the current call stack'), followed by essential usage conditions. Every sentence earns its place, and there is 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?
For a simple inspection tool with a single optional parameter, the description is nearly complete. It covers the purpose, the key precondition (paused target), and a detail (1-based lines) that could affect interpretation. It doesn't explain return format or error conditions, but given the lack of an output schema and the simplicity, it provides enough for an agent to use it correctly.
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 already fully describes the only parameter ('sessionId'), so the description doesn't need to elaborate. However, the description provides useful context that the session must be paused, indirectly clarifying that the sessionId must refer to a paused session. This adds value beyond the schema's field-level description.
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 returns the current call stack, a specific resource, and includes a critical prerequisite (requires a paused target) and a key detail (1-based lines). This distinguishes it from sibling tools that manipulate execution or breakpoints, and the purpose is immediately clear even without opening the schema.
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 a clear prerequisite ('Requires a paused target'), which implicitly tells the agent when to use it (after a pause) and when not to (during running execution). It does not explicitly name alternatives, but given the many sibling tools, this context is sufficient, as it directly implies the tool is for inspection during paused states only.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.