playcal_checkpoint

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

With no annotations at all, the description carries the full burden and falls short. It does not say whether 'save' only writes a ref or also commits/touches the working tree, whether 'restore' overwrites working files (a destructive operation), whether a git repo is a prerequisite, or how private the ref actually is.

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?

One short sentence, front-loaded with the core save-then-restore idea and no filler wording. It is efficient but under-inclusive rather than dense, so it sits just below the top score.

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 four-action tool with no annotations and no output schema, the description leaves too much uncovered: two actions are unmentioned, the destructive nature of restore is unstated, and prerequisites and return behaviour are absent. An agent could not safely invoke restore from this text alone.

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%, and the schema already explains action, target, repo and limit in more detail than the description does. The description adds no extra meaning about the checkpoint id, latest or ~N syntax, so baseline 3 applies.

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 names a concrete verb+mechanism: saving project files to a private git ref and restoring a save. That git-ref detail usefully separates it from vague neighbours like playcal_snap or playcal_baseline. It never mentions the list and diff actions, though, so it describes only half of the tool's actual surface and draws no explicit line against siblings.

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 'before each step' gives an implied trigger for the save action, which is genuine context. There is no guidance on when not to save, no mention of when to prefer playcal_snap, playcal_baseline or playcal_lock, and nothing about the list/diff workflows.

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