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

With no annotations to cover safety or side effects, the description carries the full burden and does so well: it discloses time windows (21 days, 24 hours, 7 days), the failure definition (exceptions or 5xx), the status code representation, and that rows are ordered worst-first. This gives the agent a strong behavioral model before invoking.

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 dense but every sentence contributes either operational semantics or navigation guidance, and the primary purpose is front-loaded. The middle sentence is syntactically overloaded, listing several correlated facts in one long clause, which costs some readability but not enough to drop below a 4.

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?

There is no output schema, so the description compensates by explaining row contents, ordering, and the field to inspect. It covers the main decision an agent needs to make (call this vs get_flow) and relies on the schema for parameter details. Slightly more explicit output-field structure would push it to a 5, but it is complete enough for correct invocation.

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 already documents all four parameters with 100% coverage, including defaults for limit and environment, so the baseline applies. The description adds no parameter-specific meaning beyond the schema, though it does reference the output field callersHit7d, which is return-value guidance rather than parameter semantics.

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 ('List the caller's flows'), defines what a flow is, and scopes the result to routes/jobs with traces in the last 21 days. It also distinguishes itself from the sibling get_flow by describing this as the aggregate overview and get_flow as the per-flow detail drilldown.

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?

Provides an explicit use case: 'To answer which routes are hurting callers, call this and read callersHit7d on each row.' It also names the alternative get_flow for seeing every issue behind one route, giving an agent clear routing guidance without needing to inspect sibling tools.

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