List the saved copies

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

The description goes well beyond the readOnlyHint and destructiveHint annotations by disclosing ordering, time units, and the significant behavior that unreadable manifests are omitted rather than shown as empty. It also explains why this is intentional, referencing the danger of restoring nothing and reporting success.

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?

Both sentences earn their place. The first states the core result and ordering; the second clarifies an edge case with a concrete reason. There is no redundant or filler content.

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 zero-parameter, read-only listing tool with an output schema presenthol and safety annotations, the description covers everything an agent needs: what is listed, ordering, age units, and the handling of unreadable snapshots. No critical invocation details are missing.

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 tool has zero parameters, so schema coverage is effectively complete and no parameter documentation is needed. The baseline of 4 applies because the description does not need to add parameter semantics and correctly omits them.

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 title 'List the saved copies' names a specific verb and resource, and the description expands to 'Every snapshot on this machine, newest first, with its age in seconds.' This clearly distinguishes the tool from siblings like save_snapshot and save_restore, which imply creation and restoration rather than listing.

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 makes clear this is a listing operation, so an agent can infer when to use it, but it does not explicitly state when to choose this over save_snapshot or save_restore, nor does it give exclusion criteria. The mention of save_restore is behavioral rationale, not usage guidance.

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