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

Beyond the readOnly/idempotent annotations, it discloses page size ('about 18 KB for 24 posts'), the constraint error behavior (400 rather than ignoring timeframe), case sensitivity of subreddit names, and that results use an after token for pagination. No statement contradicts 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?

The description front-loads the purpose and then packs in field names, accepted sort values, a constraint, and sibling routing. It is largely efficient, though the sort value list and field list slightly overlap with schema/enum information.

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 an output schema present and rich annotations, the description covers the remaining essentials: pagination token, sort/timeframe constraint, case sensitivity, response size, and related tools. Nothing needed for correct invocation 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%, so baseline is 3. The description adds meaningful parameter context beyond the schema: subreddit names are case-sensitive, timeframe only works with sort=top and the failure mode is a 400, and after is the pagination token.

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 opening sentence specifies a concrete action and resource: 'Returns the post stream of one subreddit with an after token to page.' It also names sibling tools for search and metadata, so an agent can distinguish it from get_reddit_subreddit_search and get_reddit_subreddit_details.

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 explicit routing: use get_reddit_subreddit_search for searching inside the same subreddit and get_reddit_subreddit_details for metadata. It also warns that timeframe is only valid with sort=top and that other combinations return 400, so the agent knows when not to supply timeframe.

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