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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the agent knows this is a destructive operation. The description adds minimal behavioral context beyond 'discard,' such as whether the change is permanently lost or how the draft is affected, but it 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 a single, front-loaded sentence that directly states the tool's purpose with no wasted words. It 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 destructive tool with three required parameters and no output schema, this description is too minimal. It does not explain what 'draftRevision' is, whether the action is irreversible, or what the outcome/return value looks like. It lacks the depth needed for an agent to invoke the tool with confidence.

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 0%, so the description must compensate by explaining the parameters. It only hints that 'endpointId' relates to an endpoint change and 'lineKey' to a line draft, but it does not clarify the role of 'draftRevision' or provide any explicit parameter semantics. This falls short of compensating for the missing schema descriptions.

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 uses a specific verb ('discard') with a specific resource ('one endpoint change from a line draft'), clearly distinguishing it from siblings like discard_line_draft (whole draft) and delete_endpoint (endpoint deletion). It conveys exactly what action is performed.

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 phrase 'from a line draft' implies the tool is used while editing a line draft to revert a single endpoint change, providing some contextual guidance. However, it does not explicitly state when to use this tool over alternatives like discard_line_draft, nor does it mention prerequisites or exclusions.

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