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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is fully covered. The description adds what the payload contains (post usage by status, token expiry), which is useful context but is also reflected in the output schema; it says nothing about auth requirements, rate limits, or what happens on a stale/invalid ID.

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 action and resource, with the payload detail trailing. No filler or repetition, and nothing an agent needs is buried.

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 single-parameter read tool with an output schema present, the description need not explain return values and is largely complete. The only gap is the absence of any routing statement toward the list sibling, which matters given 34 siblings.

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% for the single parameter, so the schema already explains socialAccountId and where to obtain it. The description only restates 'by ID' and adds no format/syntax detail beyond the schema; 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?

States a specific verb and resource ('Fetch a single connected social account by ID') and even previews the payload (status-broken-down usage, token expiry). The word 'single' implicitly contrasts with the plural list sibling, but no sibling is named explicitly, so an agent must infer the split from postnitro_list_social_accounts.

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?

No when-to-use or when-not-to-use guidance appears in the description; the only routing hint ('get from postnitro_list_social_accounts') lives in the schema, not the description. It never states the alternative for enumerating accounts, leaving the agent to infer that this is the ID-known lookup path.

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