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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds value beyond that by disclosing the shape of what comes back — full post text plus comments with nested replies — which matters because there is no output schema. It does not cover failure behavior (e.g., unknown post_id), keeping it below a 5.

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?

A single compact clause with zero filler, and the most useful detail (single post, includes comments) is front-loaded. It lacks an explicit action verb, which slightly weakens the opening.

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 simple two-parameter read tool with full annotation coverage and complete schema docs, the description supplies exactly the missing piece — the return content and nesting. No output schema exists, yet the agent still knows what to expect.

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%: 'group' explains the URL-name form and 'post_id' points back to list_posts, so the parameters are already well documented. The description adds nothing further about parameter semantics, 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?

The description names the resource precisely ('One post with its full text and comments') and even specifies the return structure (replies nested under their comment), which lets an agent separate it from bulk siblings like list_posts. The verb is only implied via the title 'Get post', so it stops short of a fully self-contained verb+resource statement.

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?

There is no explicit when-to-use guidance and no named alternative (e.g., 'use list_posts to browse, use this once you have a post_id'). The single-post framing implies the use case, but the agent must infer it.

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