cross_band

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

With no annotations, the description carries the full behavioral burden. It discloses that only near-simultaneous pairs are used and that a dust expectation is computed for comparison, which is useful. It says nothing about how pairing tolerance works, what happens when too few pairs exist, whether results are cached, or what the response contains — significant gaps for an analysis tool.

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 compact sentence with the computation and the comparison baseline front-loaded; nothing is padded. It reads as a fragment, but no sentence 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?

Six parameters, zero schema descriptions, no annotations, and no output schema make this a complex tool whose definition is one sentence. The agent lacks the pairing semantics (what tolerance_days does) and any description of the returned correlation/slope/dust-comparison structure, leaving it under-equipped to call the tool confidently.

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 0% across six parameters, so the description must compensate, and it largely does not. It clarifies the roles of series_a and series_b only implicitly through 'series A changes when series B changes'; case, start, end, and tolerance_days are never addressed, and tolerance_days is the parameter most likely to be misconfigured.

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?

The description states a concrete computation: correlation and slope dA/dB between two named series, restricted to near-simultaneous pairs, plus a dust-model comparison. That is a specific verb-plus-resource statement rather than a restatement of the name. It does not, however, distinguish the tool from plausible siblings such as compare_windows or ir_excess.

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?

There is no explicit when-to-use guidance and no named alternative. The parenthetical 'near-simultaneous pairs' hints at the data condition required, but the agent must infer that this tool is the right choice only when two bands have overlapping timestamps. No exclusions or prerequisites are given.

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