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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorld. The description adds where the payload lands ('Returns the object under community_info') and discloses the per-request cost, which the annotations do not cover. It stops short of noting rate limits or failure modes, so it is strong but not exhaustive.

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?

Three tight sentences that lead with the purpose, then usage, then return shape; the pricing note is boilerplate appended after the substance and nothing is redundant.

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?

A read-only, single-parameter lookup with an output schema in place needs only purpose, routing, and return location — all present. Annotations carry the safety profile and the output schema covers the payload fields.

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?

With 100% schema description coverage the baseline is 3, but the description adds format detail the schema lacks by specifying the ID is numeric, which helps an agent avoid passing a screen name or slug.

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 ('Get metadata for an X Community by its numeric community ID') and enumerates the returned fields (name, description, member count, access rules). It also names the sibling route for a different goal (discovery via get_twitter_community_tweets_all), so an agent can distinguish it from get_twitter_community_members, get_twitter_community_tweets, etc.

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?

Explicitly says when to use it ('qualify a community before pulling its members or posts') and provides the alternative for the adjacent task ('to discover communities by topic, search their posts with get_twitter_community_tweets_all'). This routes the agent correctly without schema inspection.

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