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

Annotations already establish read-only, idempotent, closed-world, non-destructive behavior, so the bar is lower; the description still adds the critical disclosure that private, missing, and withdrawn records all return the same 'not found' result. That non-distinguishing failure mode is exactly the kind of behavioral trait annotations cannot convey.

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?

Everything is packed into one front-loaded sentence with no filler, and the key facts (what is returned, what is not found) come first. The trailing '; or not found (...)' clause is slightly awkward to parse but still earns its place.

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?

There is no output schema, and the description compensates by listing the salient returned field and its encoding (public_key as base64url Ed25519) plus the not-found case. It does not enumerate what 'public fields' in general includes, which keeps it short of fully complete.

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 there is a single parameter, so the schema already documents 'id'. The description only restates that lookup is 'by id' and adds no format, encoding, or validation detail beyond the schema — baseline 3 applies.

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?

States a specific verb and resource ('Returns the public fields of an active, public participant record in the Weio registry by id') with the operative scope qualifiers spelled out. It does not explicitly name any sibling, so an agent must infer how it differs from registry_confirm_key, but the lookup semantics are unambiguous.

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?

Gives a concrete use case — verifying that a message was signed with the key registered on a record — which tells the agent when to reach for this tool. It stops short of naming alternatives or stating when not to use it, so it lacks the explicit routing that a 5 requires.

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