ass_list_styles

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

With no annotations, the description carries the full burden and does so well: it defines exactly what include_usage counts (all event lines, comments included) and discloses the bbox measurement's failure mode (bbox_error when ffmpeg/libass is unavailable). The only gap is that read-only/non-mutating status is only implied by 'List' rather than stated.

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?

Well front-loaded, with the core purpose in one line followed by structured Args and Returns sections. It is on the long side, but nearly every clause carries concrete semantic information rather than 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 read-only listing tool with three optional flags and no annotations, this covers purpose, each parameter's behavior, failure modes, and the return shape (style dicts, index, section, extra_fields). Nothing an agent needs to call it correctly is missing, even though an output schema also exists.

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 0%, so the description must compensate, and it does fully: doc_id (id or None for current document), include_usage (adds used and usage with its sub-keys), and include_bbox (renders BBOX_SAMPLE with libass, adds bbox ink box and bbox_error). Each parameter's shape and effect is spelled out beyond the bare 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 opening sentence states a specific verb and resource: list every style in the document. This is clearly distinct from ass_get_style (one style) and ass_list_documents (documents), though the description never names those siblings or the overlapping ass_style_usage tool. Clear, but not fully self-differentiating.

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?

Usage is implied by 'List every style in the document,' and the include_usage/include_bbox flags hint at when to reach for them. However, there is no explicit when-to-use guidance, no mention of when to prefer ass_style_usage or ass_get_style instead, and no stated prerequisites.

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