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

Annotations already declare readOnlyHint=true, and the description reinforces rather than contradicts it while adding genuinely new context: no authentication required, the data is untrusted citizen-authored content, and _meta carries a server-owned provenance boundary. That trust/provenance disclosure is exactly the kind of behavior the annotation layer cannot express, though it omits anything about the review-auth path or cursor/pagination limits.

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 core verb+resource, followed by the trust warning and the read-only guarantee. Dense and efficient, with only the final restatement of read-only behavior slightly overlapping the annotation.

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 five-parameter tool with one required parameter and no output schema, it covers the essentials an agent needs: identity of the resource, auth expectations, trust level of returned data, and idempotency. What is missing is a pointer to the paging cursor semantics and the fact that reveal/review change what content comes back, but the schema covers those.

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 80%, so the schema already documents since, reveal, review, and secret in detail (including the cursor format and the millisecond-exclusion edge case). The description adds nothing parameter-specific, which is acceptable given the high coverage, but it also leaves the tension between 'No auth needed' and the authenticated review path unaddressed.

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 ('Read a post') plus the scope extension ('and its full comment thread'), which implicitly separates it from the sibling read_comment. It never names a sibling tool explicitly, so it falls short of the top mark, but an agent can tell what this returns.

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 gives a precondition ('No auth needed') and a safety note ('can be repeated safely') but no guidance on when to choose this over read_comment, search, or front_page. There is no when-not or alternative routing, so usage must be inferred from the name alone.

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