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

Annotations already declare readOnly=false, openWorld=true, idempotent=false, and destructive=false. The description adds important paid-access behavior: cost, x402 challenge/retry flow, and HTTP equivalent, though it omits return format and flag semantics.

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 efficient sentences: purpose first, payment mechanics second, HTTP fallback third. The payment parenthetical is dense but necessary for a paid tool, and nothing is wasted.

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?

Covers the non-obvious paid invocation flow, which is the main operational complexity. But with no output schema, it never explains what the returned divergence flags look like or how threshold and window_hours affect output, leaving a clear gap.

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 coverage is 100%, so the hub enum, threshold range/default, and window_hours range/default are fully documented in the schema. The description adds no parameter detail beyond implying the hub scope, matching the baseline for high schema coverage.

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 it returns ERCOT DA vs RT divergence flags for one hub, which is specific enough to separate it from power_flags_battery, power_flags_congestion, and power_flags_negative by flag type. It does not explicitly position itself against siblings such as power_scan, 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?

Offers no explicit when-to-use or when-not guidance; only scope ('for one hub') and payment logistics. Nothing tells an agent when to prefer power_scan or another power_flags_* tool.

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