patch_canvas

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

With no annotations, the description carries the transparency burden. It discloses that the operation is a partial update ('without touching the elements') and that it returns an acknowledgment ('Returns the ack'). However, it does not mention permissions, side effects, or behavior on invalid input, leaving some gaps.

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 two sentences, front-loaded with the action and scope, and every sentence adds value (what, what-not, alternatives, return value). No redundancy or fluff.

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?

Given no annotations, no output schema, and only a 0%-coverage schema, the description is adequate for a simple patch operation but leaves gaps: 'patch' structure, 'base_rev' semantics, and any error handling are undocumented. It provides the essential context but not full completeness.

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. It lists allowed field names but does not explicitly map them to the 'patch' object parameter, nor does it explain the purpose of 'base_rev' or the structure of 'patch'. The description adds some semantic insight but fails to fully clarify parameter usage.

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 clearly states the tool's function: 'Change document-level fields' and explicitly lists the target fields (name, w, h, theme, style, font, bg, bg_image, bg_fit). It also distinguishes from sibling tools by noting it does so 'without touching the elements' and referencing update_element/set_canvas for element-level changes.

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?

Explicit guidance is given: use this tool for document-level fields, and use update_element/set_canvas for elements. This directly addresses when to use this tool vs alternatives, though the mention of set_canvas for elements is slightly ambiguous given the sibling name.

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