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

With no annotations, the description carries the full burden and largely meets it: it discloses that outcomes report conflicts or rejected edits, that removeNodeProperty is refused when the catalog requires the field (naming node and field), that an empty actions array unsets behavior, and that unacknowledged comments surface in a comments block. It still doesn't cover the token/permission model or atomicity/batch-failure semantics in the prose.

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 purpose and baseRevision/conflict model are front-loaded in the first two sentences, and each following sentence covers a distinct operation family. It is dense and slightly run-on, but no sentence is redundant filler, so it earns its length without being wasteful.

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?

This is a complex, no-annotation, mutation tool, yet the description covers the operation taxonomy, revision-conflict behavior, unset/refusal rules, and the comment-acknowledgement loop. With an output schema present, return-value details need not be spelled out, so nothing critical an agent needs to call 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 67%, and the description adds real meaning beyond it: baseRevision is framed as 'the revision you read', operationId's idempotency is echoed from the schema, and the operations array is illustrated with semantically explained patterns (name/declaration, nodeId/event/ordered actions). Only token/clientId semantics rely entirely on the schema text rather than the 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 states a specific verb and resource — applying DesignMutationV1 edits as one operation — and enumerates the concrete mutation types (insertNode, setProperty, deleteNode, moveNode, setStateVariable, setEventBinding). An agent can distinguish this mutation entry point from siblings like ui_builder_validate, ui_builder_replace_design_document and ui_builder_get_design 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 clear context for when to reach for each operation family (adding a scaffold, filling slots, setting modifiers, editing state or event behavior) and attaches conditions such as 'declare state before binding it in the batch' and 'empty actions array removes the handler'. It stops short of explicitly naming an alternative sibling or stating when not to use this tool, so it is strong context rather than a full routing guide.

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