busybar_start_timer

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

With no annotations, the description carries the full burden, and it does disclose one genuinely useful trait: the WM auto-removes the overlay when time expires, so no cleanup call is needed. However, it omits whether an already-running timer is replaced, whether other content is covered, what happens on failure, and what the call returns.

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 sentences with no filler, and the core action is front-loaded before the lifecycle note. Slightly more could be said within the same footprint, but nothing is wasted.

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?

For a mutation-style overlay tool with no annotations and no output schema, the description should cover replacement semantics, label behavior, and failure conditions. None of those are present, so an agent cannot predict the effect of calling it twice or what the label looks like.

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 only 33% — only the display enum is documented. The description adds nothing about what label renders or where, nor about durationSeconds bounds or unit, leaving two of three parameters undocumented in both places.

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?

"Start a countdown overlay on the Bar" gives a specific verb and resource, and the second sentence clarifies the lifecycle. It implicitly separates this from bar_progress (progress vs countdown) and bar_text, though it never names a sibling to contrast with.

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?

There is no when-to-use guidance: nothing says to prefer this over bar_progress, busybar_show_message, or bar_text for time-based display, and no prerequisites (e.g. bar connectivity) or exclusions are stated. The only hint of context is that it is an overlay on the Bar.

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