diff_checkpoints

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

The annotations already declare readOnlyHint=true, and the description reinforces this with 'Read-only; does not reload the editor.' It adds useful behavioral context beyond the annotations, such as the current-branch default and the fact that the editor is not reloaded.

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 three sentences with no filler. The core action is front-loaded, followed by key defaults, use guidance, and a clear exclusion. Every sentence 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?

The tool is moderately complex, with schema and annotations covering most structured details. The description adds use cases and exclusions, but because there is no output schema and the return is only described as 'change data,' the exact shape of the diff result is left unspecified.

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 covers all 4 parameters with descriptions at 100% coverage, so the baseline is 3. The description adds the current-branch default, which is also present in the schema, and does not need to compensate for missing parameter documentation.

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: 'Compute the diff between two checkpoints and return the change data.' It distinguishes itself from related siblings like list_checkpoints and restore_checkpoint, making it clear this tool is for inspecting differences rather than listing or rolling back.

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?

Explicit guidance is given: 'Use to inspect what changed before merging or restoring.' It also has a clear exclusion: 'When NOT to use: to roll back to a checkpoint (use restore_checkpoint).' This directly routes the agent to the correct alternative.

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