checkpoint_playback

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

No annotations are provided, so the description carries the disclosure burden. It does well by surfacing one-shot behavior, auto-naming, the quota cost ('1 read + local sidecar write'), and local persistence. It does not explicitly mention prerequisites like active playback or how the checkpoint can later be restored, but the main behavioral traits and side effects are disclosed.

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 two compact sentences with no filler. The core functionality and naming convention are front-loaded, and the quota/side-effect note earns its place by giving operational context.

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 tool with zero required parameters and no output schema, the description covers the essential invocation context: what it does, naming style, quota impact, and why it differs from save_playback_state. It could mention prerequisites or downstream restoration options, but those are not required to call the tool correctly.

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 both parameters already have meaningful descriptions in the schema. The tool description adds no parameter-specific detail, but with the schema fully covering note and response_format, this is acceptable at 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 description clearly identifies the tool as one-shot timestamped auto-named playback checkpoint and contrasts it with save_playback_state by saying it saves naming slots. The cp-2026-08-27T21:05 style example makes the generated naming convention concrete, leaving little ambiguity about what the tool does.

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 names save_playback_state as the alternative and gives a clear reason to choose checkpoint_playback: you avoid naming slots. However, it does not state when not to use it, nor does it mention related restore/list siblings, so the guidance is good but not exhaustive.

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