add_decorations

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

With no annotations, the description carries the full load and does so richly: stacking order for multiple items, default width from the page's short edge, height derived from aspect ratio, per-type color semantics (lines/stickers recolor, labels recolor background, text auto black/white), layering relative to a top-level node, in-place update via documentId, and the return payload (nodeId、path、盒子).

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?

Front-loaded with the action and dense with actionable detail; every clause carries information. It is a single semicolon-chained sentence, which makes it harder to scan than it could be, but there is essentially no 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 6-parameter mutation tool with no annotations and no output schema, the description covers what is created, defaults, layering, the document-passing options, return fields, and the follow-up tools. 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?

Schema coverage is already 100%, but the description still adds real meaning beyond it — how color behaves per decoration type, that text only affects labels, what `below` means in z-order terms, and the default width/height derivation. This is value on top of the schema, not restatement.

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 opens with a specific verb+resource (把装饰素材放到一页上), states batch scope (一次可放多个，按顺序叠放), and tells where decoration ids come from (list_assets 的 decorations 查 id). An agent can distinguish this from apply_actions or add_template_pages without opening any 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?

It gives concrete conditional guidance: use `below` for highlighters/tape/color blocks that must sit under text, and it states the follow-up path (改 with apply_actions, 检查 with check_document). It does not say when NOT to use this tool versus a sibling, so it falls just short of explicit alternative routing.

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