Update A2UI Data Model

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

The annotations declare destructiveHint=false, yet the description explicitly states 'remove: Delete specified keys' and 'replace: Completely replace the data model,' both of which are destructive to existing data. This directly contradicts the annotation, so per the rubric this dimension scores 1.

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 well-structured: a one-line purpose, a brief dataBinding context, a compact operations list, and an example. It is front-loaded and every sentence earns its place with no redundant 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?

The description covers the operations and includes a helpful example, so the tool can generally be invoked. However, the destructiveHint contradiction creates ambiguity about whether replace/remove are safe, and the absence of any return-behavior statement is a gap since no output schema exists. This lands at the minimum viable level.

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%, so the baseline is 3. The description adds value by explaining the semantics of each enum value (replace, merge, remove) and providing a concrete example with realistic values, which clarifies how the nested `data` object is used beyond the schema's generic description.

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 a specific verb and resource: 'Update the data model of an A2UI surface.' It differentiates from siblings like a2ui_update_components by focusing on dataBinding-backed dynamic values, and the operations list removes ambiguity about what the tool does.

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 description implies the tool is for updating a surface's dynamic data model, and the dataBinding context gives a clue. However, it never explicitly says when to use this tool instead of a2ui_update_components or other siblings, nor does it provide exclusion criteria or decision rules.

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