time_travel_diff

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

With no annotations, the description carries the full burden. It discloses that the tool returns added/deleted/changed counts, which is a useful behavioral detail. However, it does not mention read-only nature, permission requirements, performance considerations, or how edge cases (e.g., invalid snapshot IDs) are handled.

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 sentence with only 12 words. It is front-loaded and contains no filler or redundancy. Every word earns its place, making it an appropriately concise summary.

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 4 parameters, no output schema, and no annotations, the description is too sparse. It does not explain the context for using snapshots (e.g., that they belong to a specific table/namespace), nor does it describe the return structure beyond 'counts'. The tool requires more context to be used correctly, especially with no schema descriptions to fall back on.

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 0%, so the description must compensate. It references 'two snapshots', which maps to from_snapshot_id and to_snapshot_id, but gives no information about table_name or namespace, nor does it clarify which parameters are required or optional. The description adds minimal value beyond the parameter names.

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 uses a specific verb ('Compare') and resource ('two snapshots'), and clearly states the output ('added/deleted/changed counts'). This differentiates it from sibling tools like time_travel_query (query a single snapshot) and list_snapshots (list available snapshots).

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?

No guidance is provided on when to use this tool versus alternatives such as time_travel_query. The description implies a diffing use case but does not state explicit prerequisites, exclusions, or scenarios where another tool would be more appropriate.

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