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

The annotations already establish that this is a read-only, idempotent, non-destructive open-world query. The description adds useful behavioral context by naming the Arctic Shift source, listing returned fields, and explicitly warning that results are raw comments with no per-author rollup.

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 front-loaded and mostly efficient, covering scope, filters, returns, and limitations in two sentences. There is slight redundancy between 'No per-author aggregation' and 'nothing rolled up into a user profile,' but it reinforces an important limitation.

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 seven parameters, no output schema, and read-only annotations, the description supplies what an agent needs: source, required scoping, optional filters, returned fields, and the key limitation that no user-level aggregation is available.

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 parameter details are already well documented. The description still adds important semantic guidance by emphasizing that at least one of subreddit or link_id is required and by clarifying that query matches comment body text.

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 states a specific verb and resource: retrieving historical Reddit comments via Arctic Shift. It clearly distinguishes comments from posts by specifying that results are raw comments and that no per-author aggregation is performed.

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 gives clear scoping rules: use a subreddit, a specific post via link_id, or both, and at least one is required. It also explains optional keyword and date filters, though it does not explicitly contrast this tool with siblings like reddit_history_posts or subreddit_activity.

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