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

Annotations declare readOnly/idempotent/non-destructive, but the description adds behavior beyond them: a login requirement, the 50-comment cap and sort order, and precise error semantics (deleted/visibility/blocked always yield moment_not_found). Auth needs and a bounded response are exactly the kind of context 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?

Bracketed labels (login/composition/pitfalls) front-load the most decision-relevant facts and there is no filler sentence. Dense but every clause carries actionable 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 no output schema, the description fully compensates by describing the return payload (full text, likers, first 50 comments, attached cards with type/available) and the failure mode. Nothing an agent needs to invoke or chain this tool 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?

Single required parameter with 100% schema description coverage, which already documents momentId and its sourcing (list_moments_feed / get_user_moments / search_moments). The description adds no further parameter detail, so the 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 (retrieve a moment's full text, likers, and first 50 comments) and even specifies the ordering (chronological, oldest first). An agent can distinguish it from list_moments_feed, search_moments, and get_user_moments, which it implicitly contrasts against as list/search producers of momentId.

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 states the trigger ('before replying to a comment, call this to get commentId') and names the downstream alternatives in a composition chain: comment_moment(replyToCommentId) and like_moment, plus card routing to get_activity/get_product/get_need/get_organization when available=true. This is textbook when/when-next guidance.

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