cyd_step

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

No annotations are provided, so the description carries the full burden. It discloses that the tool advances by one frame and that it targets cooperatively paused apps, but it does not state what happens if the app is not paused, whether the step is reversible, or what side effects (e.g., state changes) occur. This is a significant gap for a control operation with no annotation coverage.

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 description is a single sentence and is efficient, but the phrase 'Control, any layer.' is ambiguous and adds little value. The core action is front-loaded, but the vague prefix could be removed for clarity. Overall it is concise and structurally sound.

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 tool with no parameters and no output schema, the description provides the essential precondition (cooperatively paused) and the action (advance by one frame). It is adequate for invocation, though it does not mention error conditions or return behavior, which is acceptable given the absence of an output schema.

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?

The tool has zero parameters, so the schema provides no semantic content. The baseline for 0 params is 4, and the description adds the key semantic context of 'one cyd.update() frame', which is useful but not required since there are no arguments to document.

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 ('Advance') and a clear resource ('a cooperatively paused MicroPython app'), and it specifies the action as advancing by one cyd.update() frame. This distinguishes it from siblings like cyd_resume (full resume) and cyd_pause (pause), making the purpose 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?

The description implies usage when the app is 'cooperatively paused', which is a precondition, but it does not explicitly contrast with alternatives such as cyd_resume for full continuation or cyd_tap for UI interaction. No explicit 'when-not' or alternative is named, leaving some inference to the agent.

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