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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds value by disclosing the output field `pubkey` and its downstream use as a scoping parameter, which is real behavioral context absent from annotations (no output schema exists).

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 sentences, zero filler: the purpose and topic-matching mode come first, the chaining guidance second. Bounds and defaults are delegated to the schema rather than restated.

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 two-parameter read-only search with no output schema, the description covers what the tool does, how to phrase the query, and what the result contains (a pubkey you can reuse). Nothing needed to call it correctly 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 coverage is 100% and both parameters (query, limit) are documented in the schema with examples and bounds. The description only reinforces that `query` is a free-text topic; it adds no syntax, formatting, or limit guidance beyond the schema, so 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 ("Find Nostr communities"), names the underlying data type (Communikey, kind 10222), and clarifies the matching mode is free-text topic. An agent can distinguish this from browse_* / list_* siblings immediately 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?

Gives an explicit use case with a concrete example question ("welche Community/Gruppe beschäftigt sich mit …") and explains the follow-up path: pass the returned pubkey as `community` to search_content or search_calendar_events. It stops short of stating when NOT to use it (e.g. browsing known communities via list_known_authors), so it is strong but not fully exhaustive.

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