list_snapshots

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

The description adds value beyond the readOnlyHint annotation by explaining the nature of snapshots ('Before-images taken automatically ahead of every library write') and their ordering ('newest first'). This gives the agent useful context about what the tool returns and how it's sorted. No contradictions with 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, efficient sentence that conveys the core concept and ordering. No wasted words, and the key information (what snapshots are) is front-loaded. It is concise without being under-specified.

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?

Given the simplicity of the tool (no parameters, no output schema, read-only annotation), the description is mostly complete. It tells what the tool returns (list of before-images) and the ordering. It could mention the relationship to restore_snapshot or what snapshots contain, but that's not critical for calling it 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?

The tool has zero parameters and the schema covers 100% of them (none). Per the rubric, baseline is 4 when there are no parameters. The description doesn't need to add parameter semantics since there are none.

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 resource ('Before-images taken automatically ahead of every library write') and the action (implied 'list' through the tool name and context). It distinguishes itself from siblings like restore_snapshot (which restores) and list_queries (which lists queries), so the purpose is clear enough, though it does not explicitly state 'list' as a verb.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention that it's the read-only counterpart to restore_snapshot, nor does it suggest any use case or context. The only clue is the word 'list' in the tool name, which is not elaborated.

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