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

With no annotations, the description carries the full burden. It discloses the return behavior explicitly: 'Returns the full member record if found, or a not-found message.' This covers both success and failure paths. It does not mention side effects or auth, but as a lookup, the read-only nature is implied.

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 description is three sentences, each adding essential information: the main action, the scope of roles, and the return behavior. It is front-loaded with the core purpose and has no redundant or filler text.

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?

For a simple lookup tool with one parameter and an output schema (though not shown), the description covers the necessary context: what the tool does, what input it takes, and what kind of output to expect. It is sufficiently complete for the agent to select and invoke it correctly.

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?

The schema only lists 'npub' as a required string with 0% coverage. The description adds meaning by identifying it as a 'Nostr npub' and specifying that any role's npub is accepted. This helps the agent understand the expected format and scope, compensating for the bare schema.

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 clearly states the tool's function: 'Look up a member by their Nostr npub.' It specifies the verb (look up), the resource (member), and the parameter (npub). It also adds scope by noting it can look up any role's npub (citizen, operator, or authority), which distinguishes it from role-specific sibling tools.

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 description implies usage context: this is the general lookup tool for members across all roles. It states 'Can look up any role's npub,' which tells the user when this tool is applicable. It does not explicitly name alternatives, but given that sibling tools are role-specific operations (e.g., register, confirm), the guidance is clear enough.

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