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

Goes well beyond the annotations: appends a new version and keeps the prior one (clarifying that destructiveHint=false while the call still mutates), gives the ~4 minute runtime, the ~52 second cutoff after which it returns a toolCallId and finishes in the background, and states that cancelling before it answers saves nothing. That is exactly the timing, async and cancellation context an agent cannot get from readOnlyHint/openWorldHint/idempotentHint.

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 core operation, then the async protocol, then cancellation — a sensible order with no filler. It is dense and somewhat run-on in the async section, but nearly every clause carries operational meaning.

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?

No output schema exists, and the description covers what an agent needs: what comes back on success ('still running' plus toolCallId), how to retrieve the eventual result, how many polls a long run takes, and what happens on failure or cancellation. Nothing material is missing for correct invocation.

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 designId, optionKey and instruction are already documented. The description only restates them (UUID for the design, key A/B/C for the option) without adding format or constraint detail, so baseline 3 applies.

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: refine one option of an existing UI design with a natural-language instruction, and says it appends a new version rather than replacing. It implicitly contrasts with stride.generate_ui_design by scoping to an existing design, and the designId/optionKey/instruction framing makes the operation unmistakable.

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?

Explicitly routes the agent to stride.get_tool_call_status when the tool answers 'still running', and warns that repeating the same call starts nothing. It stops short of naming generate_ui_design as the alternative for creating a new design from scratch, but the 'existing' qualifier carries most of that.

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