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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds useful lifecycle semantics for attachments (pending/stored/failed with failure_reason), which goes beyond structured fields, but since an output schema exists this partly retreads return-shape territory rather than adding operational caveats like permissions or missing-post behavior.

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?

One sentence, front-loaded with the core action and then the payload contents; no filler or repetition. The parenthetical enumerating attachment states is dense but earns its place by clarifying the status vocabulary.

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 an output schema present the description needn't enumerate return fields, and annotations cover the safety profile, so what remains is a clear one-parameter read. The only gap is the absence of any routing hint toward the list/sibling alternatives for an agent deciding how to reach a post.

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 100% for the single post_id parameter, so the schema already documents it and the description adds no format, provenance, or validity detail. Baseline 3 applies when the schema does the heavy lifting.

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 opens with a specific verb and resource ("Get one post") and scopes the payload: per-platform delivery detail plus attachment status, size and hash. The singular "one post" implicitly contrasts with the plural list_posts sibling, but it never names that sibling or states the contrast explicitly.

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?

Usage is only implied — an agent can infer this is the detail-fetch tool for a single post versus list_posts for enumeration, but no when-to-use or when-not-to-use guidance is stated. There is no mention of prerequisites such as needing a post_id obtained from list_posts or create_post.

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