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

Annotations already cover the safety profile (readOnly, non-destructive, not open-world). The description adds genuinely useful behavior beyond them: the return shape (paginated top-level comments with nested replies) and the platform-support limitation that may cause empty/unsupported results.

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?

Four sentences, each carrying content, with the core action front-loaded. No filler or redundancy, though it is slightly prose-y rather than maximally tight.

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 compensates by describing the return structure, and annotations cover safety while the schema covers all parameters. The platform-support caveat closes the last gap; only explicit pagination/return-volume guidance is absent.

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 description coverage is 100%, so all six parameters are already documented in detail, including that from/to filter on PostProxy receipt time. The description's restatement ('filter by when PostProxy received the comment with from/to') adds only marginal value over the schema, so the baseline of 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 ('List comments on a published post') and adds scope detail (paginated top-level comments with nested replies). It is clearly distinguishable from write siblings like comments_create/comments_delete, though it never explicitly names an alternative tool, keeping it short of a 5.

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?

The description implies the use context (reading comments on a post) and offers a useful caveat ('Not all platforms support comments'), but it gives no explicit when-to-use vs alternatives guidance and does not route the agent to siblings such as comments_get or profile_comments_list.

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