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

Goes well beyond the readOnly/openWorld annotations: it describes the returned tree shape (t1 entries plus 'more' placeholders with child ids and counts), the empty-result case, that timestamps and scores are historical snapshots, and that timeouts/throttles surface as 503 with Retry-After. That is exactly the operational context an agent needs before calling.

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?

Purpose is front-loaded in the first clause, then conditioning facts follow in compact sentences with no filler. It is dense but justified for a bounded-tree endpoint with meaningful fallbacks; only the defaults repeat what the schema already says.

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?

Complete for a 5-parameter read tool: identity, bounding behavior, result shape, empty case, historical-data caveat, and error behavior are all covered, and the output schema is present for structural detail.

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 defaults and ranges are already documented; the description still adds real value by stating that limit clamps to 100 and that start_breadth/start_depth are capped at 8, framing them as controls over how far the tree is expanded. parent_id is left to the schema's own explanation.

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 ('Get a bounded nested comment tree ... for one Reddit post id') and names the source (Arctic Shift's historical archive). It is immediately distinguishable from reddit_archive_comments_search, which returns flat rows.

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_archive_comments_search for flat archived comment rows,' which sets the tree-vs-flat selection rule. What's missing is a when-not condition for other siblings (e.g., live reddit_comments) or a note that the post id must come from reddit_archive_posts_search.

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