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

Adds rich context beyond the readOnlyHint/openWorldHint annotations: which fields are omitted (subscriber counts, icons, banners) and why, the 503 + Retry-After throttling contract and how to react, and the internal Redlib fallback with preserved source.type and credit weights. This is exactly the behavioral disclosure annotations cannot carry.

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?

Front-loads the core purpose, then layers in availability caveats, throttle handling, and fallback behavior in a sensible order. Five sentences is a bit dense but each earns its place; 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?

For a read-only about tool with a full output schema, the description covers purpose, omissions, failure modes, and fallback, so return values need not be explained. Auth/privacy posture is implicitly covered by anonymous-page framing, leaving only minor gaps.

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% (both parameters fully documented, including the 1-100 limit range), so the schema does the heavy lifting. The description adds no parameter-level syntax or format detail beyond what the schema already provides; baseline 3 applies.

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 — returning public metadata and sample posts for a subreddit — and explicitly contrasts with the sibling reddit_subreddit_posts. An agent can distinguish this from other reddit_* tools without opening any schema.

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 routes the agent: 'Use reddit_subreddit_posts to list Reddit subreddit posts.' This names the alternative and implies this tool is for metadata/about, but it doesn't state a positive when-to-use condition for this tool itself, so it falls just short of a full 5.

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