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

Annotations already provide readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, which cover safety and non-mutating behavior. The description adds a small note about cost ('Free') and behavior about as_of. However, it doesn't explain the return format or how the snapshot is retrieved, and with output schema absent, the description carries more burden. Given the high annotation coverage, a 2 is slightly harsh; but the description adds limited behavioral context beyond what annotations suggest.

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 three short sentences with no fluff. It front-loads the core purpose and includes the free and as_of behavior. Each sentence adds value and the structure is clean.

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 tool is a simple replay with one parameter and rich annotations, the description covers the essential usage. It doesn't describe return format but that's allowed since output schema is absent and it's a minor gap. The description is sufficient for an agent to call 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?

Schema coverage is 100%, so the parameter 'id' is well documented as a snapshot_id from a prior tool result. The description reiterates the purpose ('Replay a stored dated report') which adds slight context but doesn't provide additional parameter details beyond the schema. Thus, baseline 3 is appropriate.

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 states the action ('Replay a stored dated report') and the resource ('stored dated report'), and it distinguishes from related tools like search by noting it does not re-search or re-judge. While it doesn't explicitly name a sibling, the differentiation from search is clear.

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 indicates when to use it: to replay a stored dated report without re-searching, and clarifies that a new as_of means calling the original tool. It doesn't explicitly state what tools to use instead, but the context implies a distinction from search and analysis tools. It provides clear context for use.

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