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

With no annotations, the description carries the full behavioral burden. It discloses only that the call is free; it says nothing about authentication requirements, what happens when the npub is unknown, or whether the lookup is read-only (implied but unstated). An output schema exists, so return values need not be described, but the operational gaps remain.

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?

Two short, front-loaded sentences with no filler; the verb and identifier come first. The trailing 'Free.' fragment is terse but does convey a real constraint, so it 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?

For a one-parameter read tool with an output schema, the description covers purpose and cost, and the schema covers the return shape. What is missing is failure behavior (unknown npub) and any hint of where the member data comes from, which keeps it at minimum-viable rather than 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 description coverage is 0% for the single npub parameter, so the description must compensate. Saying 'by npub' confirms the parameter's role but adds no format detail (bech32 prefix, expected length, whether it accepts hex pubkeys), which is the bare minimum for an identifier field.

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 (look up a community member) and the key identifier (npub), which is enough to distinguish it from list_canonical_identities or get_nostr_profile at a glance. It does not explicitly name a sibling or state how it differs from the other identity-lookup tools, so it stops 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?

'Free' implies there is no payment gate, which is a mild usage signal, but the description never says when to reach for this tool versus get_nostr_profile, list_canonical_identities, or the other oracle endpoints. No prerequisites, no exclusions, no alternative routing.

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