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

The description goes beyond the destructiveHint annotation by stating that unsaved changes are permanently lost and the transaction_id can no longer be used. It also mentions the return behavior ('confirmation that the changes were discarded'), which is useful since there is no output schema.

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 short, front-loaded with the core action, and every sentence adds relevant information. There is no filler or repetition beyond what is needed for clarity.

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 cancellation tool with a destructive annotation, the description covers what happens, the side effect on transaction_id, and the confirmation return. With no output schema, a bit more detail about the confirmation response could be useful, but the current description is sufficient for an agent to invoke the tool safely.

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 coverage is 100%, so the schema already explains transaction_id and user_intent. The description adds only minor context by calling the transaction 'active' and noting the ID comes from the start operation, but it does not materially improve parameter understanding beyond the schema.

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 action ('Undo or discard all unsaved changes') and the specific resource ('active Canva editing transaction'). It also signals the opposite of saving, which differentiates it from the sibling commit-editing-transaction without needing to open that tool.

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 explicitly says when to use the tool: 'cancel a set of in-progress edits or finish editing without saving.' It does not name the commit sibling as the alternative for saving, but the context is clear enough for an agent to choose correctly.

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