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

Annotations cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds substantial behavior beyond them: the status vocabulary (confirmed, pending, expired, unknown), the split between the first anchoring as proof time and a separate latest_registration for re-registrations by possibly different holders, and the crucial caveat that a proof shows existence, not submitter identity.

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 purpose and return shape are front-loaded in the first sentence, and the later sentences carry non-redundant caveats about latest_registration and submitter anonymity. It is dense rather than padded, though the third sentence is long enough that slightly tighter phrasing would help.

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?

Even though an output schema exists and return values need not be spelled out, the description still explains the status field and the first-anchoring versus latest_registration distinction, which is exactly the ambiguity an agent would otherwise misread. Nothing needed to call or interpret the result correctly is missing.

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% and the single parameter is fully documented, so the baseline would be 3. The description adds meaning beyond the schema by revealing that the hash is mapped to a Doichain name of the form poe/<sha256>, which explains how the input is actually interpreted on chain.

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 opens with a specific verb and resource: 'Check whether a SHA-256 hash is anchored on the Doichain (name poe/<sha256>) and since when.' It also exposes the underlying name mapping, which lets an agent separate this read-only lookup from the sibling mutation tool anchor_proof without opening either schema.

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?

Usage is implied rather than stated: the read counterpart to anchor_proof is obvious from context, but there is no explicit 'use this when / use X instead' routing, nor any stated prerequisites. The verification semantics ('confirmed or expired proof shows a document existed no later than block time') hint at appropriate use but stop short of guidance.

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