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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so safety is covered structurally. The description still adds real value beyond them by disclosing the epistemic character of the result ('a hedged read with its source and date'), telling the agent the answer may be uncertain and is provenance-tagged — important context for how much to trust it.

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?

Three short sentences, front-loaded with the decision being answered, then the return shape, then the input. No filler and nothing repeated from the title or schema.

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 one-parameter, read-only tool with no output schema, the description covers purpose, the input format, and the nature of the return value (hedged, sourced, dated), which compensates for the missing output schema. Minor gaps remain around behavior for nonexistent or restricted subreddits.

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% for the single 'room' parameter, so the baseline is 3. The description goes slightly beyond the schema by noting the name may be given 'with or without r/', a format tolerance the schema's example does not state explicitly.

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 the concrete question it answers — whether a subreddit permits a founder to post, comment, or share a product link — which is a specific resource/decision rather than a restatement of the name. It does not explicitly name a distinguishing sibling, but none of the listed siblings (draft_reply, find_people_asking, validate_idea) answer this question, so confusion risk is low.

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?

Usage is implied rather than stated: an agent can infer it should call this before posting or sharing a product link in a subreddit. There is no explicit 'use when X, not Y' guidance, no prerequisites, and no statement about what to do when the subreddit is unknown or has no rules.

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