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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: the exact content returned (hashes plus anchoring transactions), the lookback cap of 30 days, and that the call is free. It stops short of describing output shape or ordering, keeping it out of 5 territory.

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 sentence front-loads what is returned, then the reason to call it, then the parameter bounds and cost. No filler, no repetition of the title, every clause does work.

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?

With one optional parameter and no output schema, the description needs to explain what comes back and why — it does both. It does not sketch the return structure (e.g., one entry per day vs. an aggregate list), which is only a minor omission for a read-only tool of this size.

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 carry the parameter's meaning — and it does, explaining that days is a lookback window ('last N days'). The 1-to-30 bounds and default 30 it cites are already encoded in the schema, so those details are partly redundant, but the semantic framing of the parameter is genuinely added.

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 states a specific resource (SHA-256 hashes of daily sealed product snapshots plus their X Layer anchor transactions) and the verb is precise enough that an agent knows exactly what comes back. It does not explicitly contrast with any sibling tool, but the other siblings (brief_preview, catalog, chain, report, etc.) are in different domains, so differentiation is implicit rather than stated.

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 clause 'so you can check that a past response was not changed later' gives a concrete use case, and 'Free' signals there is no cost barrier to calling it. There is no 'when not to use' guidance and no named alternative, so it falls short of the 5 bar.

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