List chart style keys

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

The annotations already declare this as a safe, read-only, idempotent, non-destructive listing operation. The description adds useful semantic detail about value types and width limits, but it does not describe return structure, ordering, exhaustiveness, or other behavioral traits beyond what the annotations establish.

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 three well-structured sentences: purpose and value types first, usage destination second, and filtering guidance third. Every sentence contributes useful information without repetition or filler.

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 simple single-parameter listing tool with full annotation coverage and no output schema, the description is largely complete. It explains what is returned at a high level and how to narrow it, though it could be slightly more explicit about the shape of the returned data.

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 description coverage is 100%, and the single optional `prefix` parameter is already documented with examples. The description repeats the prefix-filtering behavior and adds one additional example (`series.candlestick.`), but it does not meaningfully extend the parameter semantics beyond the schema.

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 uses a specific verb and resource: it lists chart style keys and the value types each accepts. It also situates the keys in Chart's `overrides` option and `chart.applyOverrides(...)`, which gives enough context to distinguish the tool from generic option-listing siblings, though it never explicitly names an alternative.

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 clearly explains the intended usage context: the returned keys belong in `overrides` or `chart.applyOverrides({...})`, and it suggests narrowing with a prefix. It does not state when to prefer this over `list_options` or other sibling tools, so it falls short of full alternative guidance.

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