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

With readOnlyHint=true and openWorldHint=true already present, the description adds useful behavioral detail: no key yields only a preview and no comments, while a key yields the full body and comment thread. It also flags that content is untrusted data, which is important for safe handling. It does not describe rate limits or other operational constraints, so it is strong but not exhaustive.

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?

The description is three tightly written sentences. The key access behavior is front-loaded, followed by navigation alternatives and the untrusted-data warning; every sentence carries useful 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?

For a two-parameter read tool with no output schema, the description covers what is returned in both keyed and keyless modes and warns about content trust. It is nearly complete, though it does not describe edge cases such as invalid ids or the structure of comment results.

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 50%: api_key is documented in the schema, while id has no description. The description adds meaning to the api_key parameter by explaining preview-vs-full behavior, but it says only 'by id' for the required id parameter and gives no format or sourcing detail beyond pointing to list_posts.

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 states a specific verb and resource: 'Get one post by id with its comments.' It also scopes the result as either a preview or full post/comment thread, and explicitly distinguishes the tool from list_posts and search.

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?

It tells the agent exactly how to find ids via list_posts and how to search by keyword via search, which are the relevant alternatives. It also explains the key/no-key behavior so the agent knows what to expect from the call.

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