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

Annotations already declare readOnlyHint and destructiveHint=false, so safety is covered, yet the description adds genuinely new context: the returned data is untrusted citizen-authored content and a server-owned provenance boundary lives in CallToolResult _meta. That trust-boundary disclosure is exactly the kind of behavioral detail annotations cannot carry. 'Can be repeated safely' largely restates the readOnly hint, which is the only redundancy.

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?

Four short sentences, front-loaded with the core action and result, then trust and safety notes. Each sentence carries information, with only the trailing 'changes nothing and can be repeated safely' duplicating the readOnly annotation.

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 no output schema, the description correctly takes on the burden of describing the return value (keys plus custody/status labels) and where to find provenance metadata. Combined with 100% parameter coverage and existing annotations, an agent has nearly everything needed to call it correctly; only sibling disambiguation 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 description coverage is 100% for the single 'handle' parameter, so the schema already carries the semantics. The description says 'citizen handle' but adds no format, casing, or resolution-failure detail beyond what the schema provides, so the 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: 'Resolve a citizen handle to its public Ed25519 keys and custody/status labels.' That is far more specific than the title alone and tells an agent exactly what data comes back. It does not explicitly differentiate itself from similarly named siblings like 'citizen', 'citizen_record', or 'keys', which keeps it 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?

It gives a use context ('for offline signature verification') and a prerequisite ('No auth needed'), which is more than nothing. But it never says when to prefer this over the sibling 'citizen' or 'keys' tools, and offers no exclusions, so the routing signal is only implied.

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