Undo

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

Annotations only carry idempotentHint=false and destructiveHint=false. The description adds backend-specific behavior (COM native undo vs headless DXF snapshot journal), the off-by-default history, the measured 37x cost of enabling it, and the redo-branch side effect. This goes far beyond what the annotations reveal.

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 single-sentence purpose is front-loaded, followed by three tightly focused paragraphs: backend behavior, cost with cheaper alternative, and redo side-effect caveat. Every sentence earns its place with no filler.

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?

Covers purpose, backend differences, required configuration, performance cost, cheaper alternatives, and the redo-discard side effect, which is nearly everything an agent needs. It does not state the return value or behavior when there is nothing to undo, and no output schema exists to fill that gap; these are minor omissions.

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 zero properties, so the 0-parameter baseline of 4 applies. The description adds the EZDXF_UNDO_DEPTH environment variable as the only relevant configuration knob, which is adjacent to parameters but not one itself, so it slightly exceeds the baseline.

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 opening sentence states a specific verb and resource: 'Undo the last drawing operation.' It is immediately distinguishable from destructive siblings like entity_delete and from transaction_rollback, which the description explicitly names and differentiates.

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?

Gives explicit when-to-use guidance: on the headless backend history is off by default and requires setting EZDXF_UNDO_DEPTH, and it names transaction_begin/transaction_rollback as the far cheaper alternative for a single checkpoint. The redo-discard caveat further informs correct usage.

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