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

Annotations declare non-read-only, non-idempotent, open-world behavior; the description adds genuinely new context beyond them: quota consumption (6/day) and the return shape ('per-account counts'). It does not cover failure/partial-sync behavior or latency, but the quota disclosure is exactly the kind of operational cost an agent needs.

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?

Three short sentences, each doing distinct work (action, cost, return), with the verb and scope front-loaded. No filler.

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 parameterless, no-output-schema tool, the description covers action, cost, and return summary, which is close to sufficient. It could be more complete by noting that it syncs all accounts unconditionally or what happens on quota exhaustion, but nothing essential to invoking it correctly is missing.

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 tool takes zero parameters, so the schema carries no semantic burden and there is nothing for the description to disambiguate. Baseline 4 for a parameterless tool.

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 fresh metrics') plus the scope ('every connected TikTok/Instagram account'), which distinguishes it from the sibling get_metrics_daily by implying a live pull rather than a stored-data read. It stops short of naming that sibling explicitly, so differentiation requires inference.

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 quota note ('Consumes the daily quota (6/day)') implies this is a costly, deliberate action and hints at when to prefer cheaper read tools, but it never states when to sync versus using get_metrics_daily or get_performance_summary. Usage is implied, not specified.

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