open_gui_tool

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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it delivers: it flags the operation as read-only, running in background, idempotent with reuse semantics, and dependent on an optional extra and a built dist. Minor omissions remain (what 'healthy' means, failure behavior when prerequisites are unmet), but the safety profile is unusually well covered for an annotation-free tool.

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?

Two tight paragraphs, zero filler. The primary action and return value are front-loaded in the first sentence, followed by a compact idempotency note and prerequisite line. Every sentence adds distinct value.

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 is largely complete for a 4-parameter launch tool with an output schema: it covers purpose, background execution, idempotency, browser behavior, and setup prerequisites. The remaining gaps — precise semantics of project_path and the definition of a 'healthy' viewer — are real but minor and do not block 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 0%, so the description must compensate. It adds meaning to host/port (the reuse key for an existing viewer) and to open_browser ('optionally opens the browser to this project'). However, project_path, the only required parameter, is never explicitly defined beyond the vague 'this project' — the agent must infer whether it points to a project directory, a manifest, or the built dist. This partial compensation warrants a 3.

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 pairing: 'Start the read-only DAW web viewer (background) and return its URL.' This clearly states the action, the object, the execution mode (background), and the return value. It is unambiguously distinguishable from the sibling tools, none of which launch a GUI viewer.

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 provides clear context for when and how to call the tool, including the idempotency guarantee (reuses a healthy existing viewer on host:port) and explicit prerequisites ('Requires the gui extra ... and a built gui/web dist'). It does not name alternatives or explicit when-not-to-use conditions, but no sibling tool is a plausible substitute.

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