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

Annotations already declare readOnly, idempotent, non-destructive, non-open-world, so the safety profile is covered. The description adds genuine behavioral context beyond that: an unknown id returns not-found rather than a guess, and the tool accepts only an id. Return format/pagination is not described, which is the only real gap.

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?

Front-loaded with what is retrieved, then usage, then the exclusion. Four tight sentences with no filler; the anti-pattern warning is placed where it matters most.

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 enumerates the returned fields, plus the not-found behavior for unknown ids. For a single-parameter read tool this is 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 coverage is 100% and the schema itself supplies an example ('indie-tlv'), so the baseline is 3. The description adds a real constraint beyond the schema: 'it takes an id and nothing else', telling the agent no other filters are accepted on this path.

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+resource ('Retrieve one community by its directory id') and enumerates the returned fields (join link, platform, region, topic, member count). It also contrasts itself against search_communities, so an agent can distinguish it from siblings 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?

Explicit when-to-use ('to answer a specific question about one group', or after search_communities to fill in join links) and explicit when-not ('Do not call it to discover communities... Search first'). The alternative tool is named, and the ordering constraint is stated.

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