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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds useful context beyond those: 'reaches no network, never changes' and describes the output content (units, upstream operation, bucketing). No contradiction with annotations; the added network and output details justify above-baseline credit.

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?

Two compact sentences with no wasted words. The first sentence front-loads the exact purpose and scope; the second adds usage trigger and behavioral constraints. Every clause earns its place.

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-argument read-only tool with annotations and an output schema, the description is fully sufficient. It states what is returned, why a user would call it, and what side effects to expect (none). Nothing an agent needs to invoke 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 has zero parameters and 100% schema description coverage, so the baseline is 4. The description reinforces this with 'Takes no arguments,' which is redundant but harmless. There is no parameter ambiguity to compensate for.

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 names a specific verb ('List') and a precise resource ('market-condition factors Regimen slices performance by'), and specifies the detail level: units, upstream operation, and bucketing. This clearly distinguishes it from sibling tools like regimen_evaluate_track_record or regimen_regime_map, which are about evaluation and mapping rather than describing factor keys.

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?

It gives an explicit call-when: 'when you need to know which factor keys exist or how to explain a bucket to a user.' It does not explicitly name when-not-to-use or alternative tools, but the phrasing implies this is for descriptive/explanation tasks rather than evaluation or regime mapping. Clear context, but no formal exclusions.

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