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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is fully covered. The description adds the return payload shape (counts, average and maximum depth, affected transaction count), which matters because there is no output schema, but it leaves 'over windows' undefined — no default range, granularity, or pagination behavior.

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?

A single front-loaded sentence with concrete metrics and no filler; every clause carries information. It is slightly under-specified rather than verbose — the 'over windows' qualifier is the one fragment that does not resolve to anything concrete.

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-argument aggregation tool with no output schema, the description usefully lists the metrics returned and carries the read-only safety profile via annotations. It is still incomplete on the two things an agent needs: what 'windows' means (time range, bucket size) and how this differs from the sibling 'reorgs' tool.

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 takes zero parameters, so the baseline is 4; the schema needs no textual compensation. The phrase 'over windows' hints at a windowing concept that has no corresponding input, a minor ambiguity, but nothing is left undocumented.

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 ('Aggregate') plus resource ('reorg statistics') and enumerates the reported metrics (counts, average/max depth, affected transactions), so an agent can tell what it produces. It never distinguishes itself from nearby siblings like reorgs, recent_orphans, or chain_fork_window, so it falls short of a 5.

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?

There is no explicit when-to-use guidance, no prerequisites, and no named alternative. With siblings such as 'reorgs' (likely the raw list) and 'recent_orphans' present, the agent must guess whether this is the summary view or a duplicate, which is exactly the ambiguity usage guidance should resolve.

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