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

Annotations already establish read-only and open-world behavior; the description adds pagination expectations ('Returns a list (use cursor when paginated)'). It also reinforces that this is a feed listing rather than a search, adding useful behavioral context beyond the annotations.

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 concise clauses convey purpose, the alternative tool, and pagination behavior with no filler. The most important decision-relevant fact ('no keyword') is front-loaded before the sibling pointer.

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 4-parameter tool with a rich schema and read-only annotations, the description covers the essential invocation details, including pagination. It does not describe the shape of returned posts, but the lack of an output schema is partially mitigated by naming the resource as a post feed.

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 100%, so the parameters are fully documented in structured form. The description adds a small amount of semantic context (feed sorts and cursor usage) but does not need to extensively explain parameters.

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 opens with a specific verb and resource: 'List a subreddit's post feed'. It also signals the key limitation ('no keyword') and distinguishes this tool from a keyword search, so an agent immediately knows what the tool does and does not do.

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?

It explicitly tells the agent to use the sibling search tool 'reddit.subreddit.search.list' when keyword search is needed, giving both when-to-use and when-not-to-use guidance. The alternative maps directly to the sibling reddit_subreddit_search_list.

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