reddit_search_communities

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds behavioral context by stating that the tool returns matching subreddits with specific fields and that NSFW results can be excluded (via schema param). This goes beyond annotations, though it doesn't detail pagination behavior or rate limits.

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, front-loaded with the core function, followed by return fields, usage context, and an example. Every sentence earns its place with no redundancy or filler.

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 search tool with 4 parameters and no output schema, the description covers the essential aspects: what it searches, what it returns, and a concrete example. It does not explicitly explain pagination, but the schema's 'after' parameter covers that. The usage guidance connects well to sibling tools, making it nearly 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 each parameter has a detailed description. The description adds one concrete example (q='machine learning') and the general 'by name or topic' clarification, but this only slightly augments the schema's already thorough parameter documentation. Baseline 3 is appropriate.

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 verb and resource: 'Search for subreddits (communities) by name or topic.' It also lists return fields (title, subscriber count, description, NSFW flag), and the usage context ('discover where a topic is discussed') distinguishes it from sibling tools like reddit_search which search posts/comments.

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 gives clear usage context: 'Use to discover where a topic is discussed before listing or searching its posts.' This implies the tool should be used first to find subreddits, then other tools for posts. However, it does not explicitly name alternatives or state when not to use it, so it falls short of a 5.

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