flow_usage_today

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

No annotations are supplied, so the description carries the behavioral burden. It does add meaningful context beyond the name — the data comes from a local log and the spend figure is an estimate, not a billed amount — implying the numbers may be machine-local and approximate. It says nothing about what happens when the log is empty, whether historical days are available elsewhere, or how current the data is.

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?

A single front-loaded sentence with no filler; the scope qualifier and the data source are packed in without redundancy. Nothing here is wasted or 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 zero-parameter read tool with no output schema, the description fully covers what is returned (count and estimated spend) and where it comes from (local log). Minor gaps remain around empty-log behavior and staleness, but an agent has enough to know what this call yields.

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 per the baseline this scores 4. The description correctly frames the scope as 'today' rather than leaving time range ambiguous, which is the only meaningful semantic decision for a no-arg call.

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 ("Show") and two concrete returned values ("today's generation count and estimated spend"), which lets an agent tell this apart from cost-estimation siblings like flow_estimate_cost. It does not explicitly name or contrast any sibling, so it stops short of a 5.

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?

"Today's" and "from the local log" imply when this applies (a historical/usage lookup rather than a forward-looking estimate), but there is no explicit when-to-use or when-not-to-use statement and no named alternative for cost forecasting versus recorded spend.

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