ass_add_lines

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

With no annotations, the description carries the full burden and does well: it explains that insert positions are 0-based, that indices resolve against the in-progress list (earlier inserts of the same call already placed), that omitted indices append, and that times accept ms or time strings. It does not cover permissions or failure behavior, but the mutation semantics are unusually well disclosed.

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?

Purpose is front-loaded in the first sentence, followed by necessary schema detail and the return shape. The key enumeration is long but each element adds meaning; no filler sentences.

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?

An output schema exists, so the return description is a bonus rather than a necessity, and the insertion-ordering semantics are fully specified for a mutation tool. The only omission is any mention of doc_id or which document the operation targets.

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%, so the description must compensate, and it comprehensively enumerates the accepted dict keys (start_ms/end_ms/text/style/actor/effect/layer/comment/margins) plus the optional index and time-format flexibility. The optional doc_id parameter is never mentioned, which is the only gap.

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 a specific verb and resource ('Append several lines in one call') and implicitly distinguishes itself from the singular sibling ass_add_line by referencing its keys and the batch nature ('in one call'). An agent can identify this as the bulk-append variant without opening the schema.

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?

The phrase 'in one call' hints that this is the efficient batch alternative to repeated ass_add_line invocations, but there is no explicit when-to-use/when-not guidance or named alternative. Usage is implied rather than stated.

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