n8n_debug_last_error

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

Annotations already declare readOnlyHint: true, so the safety profile is covered. The description adds some context about what is returned (failing node and error message) but does not disclose additional behavioral details such as response format or edge cases. It also does not contradict the annotations.

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 two concise sentences with no redundant wording. The core functionality is front-loaded, followed by a useful usage directive. Every sentence contributes value.

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 read-only diagnostic tool with one optional parameter and no output schema, the description covers what it does, what it returns, and when to use it. Nothing essential is missing for an agent to invoke 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?

Schema description coverage is 100% for the single optional workflowId parameter. The description restates that the workflow is optional ('optionally for one workflow'), which aligns with the schema but adds little beyond it. The baseline of 3 is appropriate because the schema carries the parameter meaning.

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 states a specific verb and resource: 'Get the most recent failed execution' with the failing node and error message. This clearly distinguishes it from related execution tools like n8n_list_executions and n8n_get_execution by focusing on the most recent failure.

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 gives clear usage context: 'Use this to repair a broken workflow.' It does not explicitly mention alternatives or when not to use it, but the intended scenario is clear and actionable.

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