bip_set_state

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 supply useful context that this drives physical hardware over USB Serial. It omits what happens when the device is disconnected, whether the set state persists until changed, and how gaze/speaking interact with the state enum, which matters for a stateful hardware mutation.

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?

A single front-loaded sentence that enumerates the controllable surfaces with zero filler. It is slightly list-like and could be tightened, 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 five-parameter hardware-control tool with no output schema, the description covers the what but not the interaction model: it never clarifies whether the 'blink' boolean and the 'blink' state value are equivalent or whether gaze/speaking flags override the state. That ambiguity is the main gap an agent would hit in practice.

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 ranges, the state enum, and each field's meaning are already documented. The description merely summarizes those parameters and adds no precedence or combination rules beyond the schema, making the baseline 3 appropriate.

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 ('Set') and the resource (BIP's facial expression, gaze, speaking animation, blink) and even names the transport (USB Serial). It never references the siblings, so an agent must infer that bip_speak is the text-to-speech counterpart while this only drives the mouth animation, but the operation itself is unambiguous.

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?

Usage is implied by the enumerated capabilities rather than stated: nothing says when to prefer this over bip_speak or bip_play_timeline, nor whether animations from bip_play_timeline take precedence. An agent can guess the intent, but the choice among siblings is left to inference.

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