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

Annotations already cover readOnly, destructive and openWorld, so the bar is lower, and the description still adds real value beyond them: it warns the return is untrusted citizen-authored data and that CallToolResult _meta carries a server-owned provenance boundary. Restating 'READ-ONLY... can be repeated safely' duplicates the annotation rather than adding to it, which keeps it just short of a 5.

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?

Purpose and return shape are front-loaded in the first sentence, and the custody-object clarification is well placed. A few clauses are dense ('both the registry-minted and citizen-stated dates') and the read-only sentence partly repeats the annotation, but nothing is wasted at the paragraph level.

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 usefully enumerates what comes back (keys, custody declarations, status) and where provenance lives, and it carves out custody as a structured object with dates. It does not say what happens on an unknown or unregistered handle, which is the main remaining gap for a lookup 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?

There is a single required 'handle' parameter at 100% schema description coverage, so the schema already carries the semantics. The description echoes the concept ('Resolve a citizen handle') but adds no format, normalization, or accepted-syntax guidance, which lands on the baseline 3.

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, custody declarations and status') plus the intended use ('offline signature verification'). That is concrete enough to separate it from siblings like keys, citizen, citizen_record and witnesses without opening a 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?

The phrase 'for offline signature verification' implies the situation to use this rather than a live lookup, and 'No auth needed... can be repeated safely' gives practical context. But no alternative tool is named and no when-not condition is stated, so the agent must infer routing from sibling names alone.

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