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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description's 'Get' is consistent and adds no contradiction. The description offers no additional behavioral context beyond those annotations, such as potential 404 behavior or data freshness, but the safety profile is already well covered by annotations.

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 a single, short sentence that immediately states the action, target resource, and selection criterion. There is no redundant phrasing or filler, making it optimally concise and front-loaded.

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?

The output schema and annotations cover the return shape and the safety profile, so those do not need to be described. However, the description promises fetching 'by ID' while the input schema defines no parameters, leaving an agent without enough information to actually supply the ID in a call.

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?

The input schema is completely empty, so the description's mention of 'by ID' is the only place an agent learns that an ID is conceptually required. Since 0 parameters has a baseline of 4, the description adds meaningful semantic value, though the schema does not specify how or where this ID should be provided.

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 uses a specific verb ('Get') and an exact resource ('a single post by ID'), which clearly distinguishes it from sibling tools like getPosts (plural) and createPost. An agent can immediately understand what this tool returns and how it differs.

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 phrase 'by ID' implies this is the right tool when the agent already knows a specific post ID, rather than needing a list of posts. However, it never explicitly mentions alternatives like getPosts for fetching multiple posts or createPost for creating, so the routing guidance is only implied, not stated.

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